##### 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'"                                                                                        
}

```

except Exception as e:
            if os.path.exists(tmpsrc):
                os.remove(tmpsrc)
            module.fail_json(msg="failed to copy %s to %s: %s" % (tmpsrc, dest, to_native(e)),
                             exception=traceback.format_exc(), **result)
        result['changed'] = True
    else:
        result['changed'] = False
        if os.path.exists(tmpsrc):
            os.remove(tmpsrc)
    if checksum != '':
        destination_checksum = module.digest_from_file(dest, algorithm)
        if checksum != destination_checksum:
            os.remove(dest)
            module.fail_json(msg="The checksum for %s did not match %s; it was %s." % (dest, checksum, destination_checksum), **result)
    
    file_args = module.load_file_common_arguments(module.params, path=dest)
    result['changed'] = module.set_fs_attributes_if_different(file_args, result['changed'])
    
    try:
        result['md5sum'] = module.md5(dest)
    except ValueError:
        result['md5sum'] = None
    if backup_file:
        result['backup_file'] = backup_file
    
    module.exit_json(msg=info.get('msg', ''), status_code=info.get('status', ''), **result)
if __name__ == '__main__':
    main()