<!--- Verify first that your issue is not already reported on GitHub -->
<!--- Also test if the latest release and devel branch are affected too -->
<!--- Complete *all* sections as described, this form is processed automatically -->

##### SUMMARY
<!--- Explain the problem briefly below -->
The module docker_login save the config.json with 644 permission instead of 600 (default by docker login command)
##### ISSUE TYPE
- Bug Report

##### COMPONENT NAME
<!--- Write the short name of the module, plugin, task or feature below, use your best guess if unsure -->
docker_login
##### ANSIBLE VERSION
<!--- Paste verbatim output from "ansible --version" between quotes -->
```paste below
ansible 2.8.3
  config file = /etc/ansible/ansible.cfg
  configured module search path = [u'/home/gael/.ansible/plugins/modules', u'/usr/share/ansible/plugins/modules']
  ansible python module location = /usr/lib/python2.7/dist-packages/ansible
  executable location = /usr/bin/ansible
  python version = 2.7.12 (default, Dec  4 2017, 14:50:18) [GCC 5.4.0 20160609]
```

##### CONFIGURATION
<!--- Paste verbatim output from "ansible-config dump --only-changed" between quotes -->
```paste below

```

##### OS / ENVIRONMENT
<!--- Provide all relevant information below, e.g. target OS versions, network device firmware, etc. -->
Ubuntu 18.04 server

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

<!--- Paste example playbooks or commands between quotes below -->
```yaml
- name: Log into private registry and force re-authorization
  docker_login:
    registry: "{{ registry_host }}"
    username: "{{ registry_user }}"
    password: "{{ vault_registry_password }}"
```

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

##### EXPECTED RESULTS
<!--- Describe what you expected to happen when running the steps above -->
ll /root/.docker/config.json 
-rw------- 1 root root 181 Jan 10 10:53 /root/.docker/config.json

##### ACTUAL RESULTS
<!--- Describe what actually happened. If possible run with extra verbosity (-vvvv) -->
ll /root/.docker/config.json 
-rw-r--r-- 1 root root 181 Jan 10 10:53 /root/.docker/config.json
<!--- Paste verbatim command output between quotes -->
```paste below

```

state:
    version_added: '2.3'
    description:
      - This controls the current state of the user. C(present) will login in a user, C(absent) will log them out.
      - To logout you only need the registry server, which defaults to DockerHub.
      - Before 2.1 you could ONLY log in.
      - Docker does not support 'logout' with a custom config file.
    type: str
    default: 'present'
    choices: ['present', 'absent']
extends_documentation_fragment:
  - docker
  - docker.docker_py_1_documentation
requirements:
  - "L(Docker SDK for Python,https://docker-py.readthedocs.io/en/stable/) >= 1.8.0 (use L(docker-py,https://pypi.org/project/docker-py/) for Python 2.6)"
  - "L(Python bindings for docker credentials store API) >= 0.2.1
    (use L(docker-pycreds,https://pypi.org/project/docker-pycreds/) when using Docker SDK for Python < 4.0.0)"
  - "Docker API >= 1.20"
author:
  - Olaf Kilian (@olsaki) <olaf.kilian@symanex.com>
  - Chris Houseknecht (@chouseknecht)
'''
EXAMPLES = '''
- name: Log into DockerHub
  docker_login:
    username: docker
    password: rekcod
- name: Log into private registry and force re-authorization
  docker_login:
    registry: your.private.registry.io