##### SUMMARY
<!--- Explain the problem briefly below -->

get_url fails to find the file from sha256sum.txt file, even if it is there and works fine while being done manually.

##### ISSUE TYPE
- Bug Report

##### COMPONENT NAME
<!--- Write the short name of the module, plugin, task or feature below, use your best guess if unsure -->

get_url

##### ANSIBLE VERSION
<!--- Paste verbatim output from "ansible --version" between quotes -->
```
ansible 2.9.11
```

##### CONFIGURATION
<!--- Paste verbatim output from "ansible-config dump --only-changed" between quotes -->
```
ANSIBLE_NOCOWS(/root/hetzner-ocp4/ansible.cfg) = True
ANSIBLE_PIPELINING(/root/hetzner-ocp4/ansible.cfg) = True
ANSIBLE_SSH_ARGS(/root/hetzner-ocp4/ansible.cfg) = -o ControlMaster=auto -o ControlPersist=600s
ANSIBLE_SSH_CONTROL_PATH(/root/hetzner-ocp4/ansible.cfg) = %(directory)s/%%h-%%r
DEFAULT_CALLBACK_WHITELIST(/root/hetzner-ocp4/ansible.cfg) = ['profile_tasks']
DEFAULT_FORKS(/root/hetzner-ocp4/ansible.cfg) = 20
DEFAULT_GATHERING(/root/hetzner-ocp4/ansible.cfg) = smart
DEFAULT_LOG_PATH(/root/hetzner-ocp4/ansible.cfg) = /root/ansible.log
DEFAULT_REMOTE_USER(/root/hetzner-ocp4/ansible.cfg) = root
DEFAULT_TIMEOUT(/root/hetzner-ocp4/ansible.cfg) = 30
HOST_KEY_CHECKING(/root/hetzner-ocp4/ansible.cfg) = False
INVENTORY_IGNORE_EXTS(/root/hetzner-ocp4/ansible.cfg) = ['secrets.py', '.pyc', '.cfg', '.crt', '.ini']
RETRY_FILES_ENABLED(/root/hetzner-ocp4/ansible.cfg) = False
RETRY_FILES_SAVE_PATH(/root/hetzner-ocp4/ansible.cfg) = /root/ansible-installer-retries

```

##### OS / ENVIRONMENT
<!--- Provide all relevant information below, e.g. target OS versions, network device firmware, etc. -->

centos-release-8.2-2.2004.0.1.el8.x86_64


##### STEPS TO REPRODUCE
<!--- Describe exactly how to reproduce the problem, using a minimal test-case -->

I have file to download, and a checksum file for it. The following urls are used:

https://mirror.openshift.com/pub/openshift-v4/dependencies/rhcos/4.5/4.5.6/sha256sum.txt
https://mirror.openshift.com/pub/openshift-v4/dependencies/rhcos/4.5/4.5.6/rhcos-4.5.6-x86_64-qemu.x86_64.qcow2.gz



<!--- Paste example playbooks or commands between quotes below -->
```yaml
    - name: download coreos
      get_url:
        url: "{{ coreos_download_url }}"
        dest: "{{ coreos_path }}/{{ coreos_file }}.gz"
        checksum: "sha256:{{ coreos_csum_url }}"
      register: coreos_download

```

<!--- HINT: You can paste gist.github.com links for larger files -->

##### EXPECTED RESULTS
<!--- Describe what you expected to happen when running the steps above -->

If I do this manually, it works fine:

```
# wget https://mirror.openshift.com/pub/openshift-v4/dependencies/rhcos/4.5/4.5.6/sha256sum.txt
# wget https://mirror.openshift.com/pub/openshift-v4/dependencies/rhcos/4.5/4.5.6/rhcos-4.5.6-x86_64-qemu.x86_64.qcow2.gz
# grep rhcos-4.5.6-x86_64-qemu.x86_64.qcow2.gz sha256sum.txt |sha256sum -c
rhcos-4.5.6-x86_64-qemu.x86_64.qcow2.gz: OK
```

##### ACTUAL RESULTS
<!--- Describe what actually happened. If possible run with extra verbosity (-vvvv) -->

The correct line is in checksum file:
```
# grep rhcos-4.5.6-x86_64-qemu.x86_64.qcow2.gz sha256sum.txt              
a94f3cd6113839f61239e42887bce7c2c0d6742e2e35d775c5786f5848f208fc  rhcos-4.5.6-x86_64-qemu.x86_64.qcow2.gz
```


<!--- Paste verbatim command output between quotes -->
```paste below
Using module file /usr/lib/python3.6/site-packages/ansible/modules/net_tools/basics/get_url.py                                         
Pipelining is enabled.                                                                                                                 
<127.0.0.1> ESTABLISH LOCAL CONNECTION FOR USER: root                                                                                  
<127.0.0.1> EXEC /bin/sh -c '/usr/bin/python3.6 && sleep 0'                                                                            
fatal: [localhost]: FAILED! => {                                                                                                       
    "changed": false,                                                                                                                  
    "invocation": {                                                                                                                    
        "module_args": {                                                                                                               
            "attributes": null,                                                                                                        
            "backup": null,                                                                                                            
            "checksum": "sha256:https://mirror.openshift.com/pub/openshift-v4/dependencies/rhcos/4.5/4.5.6/sha256sum.txt",             
            "client_cert": null,                                                                                                       
            "client_key": null,                                                                                                        
            "content": null,                                                                                                           
            "delimiter": null,                                                                                                         
            "dest": "/var/lib/libvirt/images/rhcos-4.5.6.qcow2.gz",                                                                    
            "directory_mode": null,                                                                                                    
            "follow": false,                                                                                                           
            "force": false,                                                                                                            
            "force_basic_auth": false,                                                                                                 
            "group": null,                                                                                                             
            "headers": null,                                                                                                           
            "http_agent": "ansible-httpget",                                                                                           
            "mode": null,                                                                                                              
            "owner": null,                                                                                                             
            "regexp": null,                                                                                                            
            "remote_src": null,                                                                                                        
            "selevel": null,                                                                                                           
            "serole": null,                                                                                                            
            "setype": null,
            "seuser": null,                                                                                                            
            "sha256sum": "",
            "src": null,
            "timeout": 10,
            "tmp_dest": null,
            "unsafe_writes": null,                                                                                                     
            "url": "https://mirror.openshift.com/pub/openshift-v4/dependencies/rhcos/4.5/4.5.6/rhcos-4.5.6-x86_64-qemu.x86_64.qcow2.gz",
            "url_password": null,
            "url_username": null,                                                                                                      
            "use_proxy": true,
            "validate_certs": true
        }
    },                                                                                                                                 
    "msg": "Unable to find a checksum for file 'rhcos-4.5.6-x86_64-qemu.x86_64.qcow2.gz' in 'https://mirror.openshift.com/pub/openshift-
v4/dependencies/rhcos/4.5/4.5.6/sha256sum.txt'"                                                                                        
}

```

time and replace the file if the contents change. If C(no), the file
        will only be downloaded if the destination does not exist. Generally
        should be C(yes) only for small local files.
      - Prior to 0.6, this module behaved as if C(yes) was the default.
      - Alias C(thirsty) has been deprecated and will be removed in 2.13.
    type: bool
    default: no
    aliases: [ thirsty ]
    version_added: '0.7'
  backup:
    description:
      - Create a backup file including the timestamp information so you can get
        the original file back if you somehow clobbered it incorrectly.
    type: bool
    default: no
    version_added: '2.1'
  sha256sum:
    description:
      - If a SHA-256 checksum is passed to this parameter, the digest of the
        destination file will be calculated after it is downloaded to ensure
        its integrity and verify that the transfer completed successfully.
        This option is deprecated and will be removed in version 2.14. Use
        option C(checksum) instead.
    default: ''
    version_added: "1.3"
  checksum:
    description:
      - 'If a checksum is passed to this parameter, the digest of the
        destination file will be calculated after it is downloaded to ensure
        its integrity and verify that the transfer completed successfully.