<!--- 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 -->
When logging out from any Repository the play aborts with Message "TypeError: 'in <string>' requires string as left operand, not bytes". Our Ansible is using Python 3!

I found that the docker_login is searching for Bytes in the output of the 'docker logout..' command (e.g. _elif b'Removing login credentials for ' in out_). I changed this in my local Ansible code to strings to fix that. I cannot verify this with Python 2.x

##### 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 2.8.5
  config file = /home/app/nondocker/ansible/ansible.cfg
  configured module search path = ['/home/app/.ansible/plugins/modules', '/usr/share/ansible/plugins/modules']
  ansible python module location = /home/app/containervol/python/python3/lib/python3.7/site-packages/ansible
  executable location = /home/app/containervol/python/python3/bin/ansible
  python version = 3.7.4 (default, Jul 30 2019, 19:56:38) [GCC 7.3.1 20180712 (Red Hat 7.3.1-6)]
```

##### CONFIGURATION
<!--- Paste verbatim output from "ansible-config dump --only-changed" between quotes -->
```paste below
ANSIBLE_PIPELINING(/home/app/nondocker/ansible/ansible.cfg) = True
DEFAULT_HOST_LIST(env: ANSIBLE_INVENTORY) = ['/home/app/nondocker/SVN/trunk/Deploy_Artefakte/ansible/inventory.yml']
DEFAULT_LOG_PATH(/home/app/nondocker/ansible/ansible.cfg) = /home/app/nondocker/ansible/logs/ansible.log
DEFAULT_MANAGED_STR(/home/app/nondocker/ansible/ansible.cfg) = Ansible managed file - do not make changes here - they will be overwritten during next deployment!
```

##### OS / ENVIRONMENT
<!--- Provide all relevant information below, e.g. target OS versions, network device firmware, etc. -->
NAME="Amazon Linux"
VERSION="2"
ID="amzn"
ID_LIKE="centos rhel fedora"
VERSION_ID="2"
PRETTY_NAME="Amazon Linux 2"

##### 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 out of docker-hub-remote.bahnhub.tech.rz.db.de:443"
  docker_login:
    registry:   'docker-hub-remote.bahnhub.tech.rz.db.de:443'
    state:       absent
```

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

##### EXPECTED RESULTS
<!--- Describe what you expected to happen when running the steps above -->
Successful logout of the Docker Repository.

##### ACTUAL RESULTS
<!--- Describe what actually happened. If possible run with extra verbosity (-vvvv) -->
2019-09-17 17:21:07,741 p=27466 u=app |  <elokfiku-tst-app.dbv2-test.comp.db.de> EXEC /bin/sh -c '/home/app/containervol/python/python3/bin/python /home/app/.ansible/tmp/ansible-tmp-1568733667.5645123-182000990462949/AnsiballZ_docker_login.py && sleep 0'
2019-09-17 17:21:08,101 p=27466 u=app |  fatal: [test_app]: FAILED! => {
    "changed": false,
    "module_stderr": "/home/app/.ansible/tmp/ansible-tmp-1568733667.5645123-182000990462949/AnsiballZ_docker_login.py:68: DeprecationWarning: the imp module is deprecated in favour of importlib; see the module's documentation for alternative uses\n  import imp\nTraceback (most recent call last):\n  File \"/home/app/.ansible/tmp/ansible-tmp-1568733667.5645123-182000990462949/AnsiballZ_docker_login.py\", line 262, in <module>\n    _ansiballz_main()\n  File \"/home/app/.ansible/tmp/ansible-tmp-1568733667.5645123-182000990462949/AnsiballZ_docker_login.py\", line 252, in _ansiballz_main\n    invoke_module(zipped_mod, temp_path, ANSIBALLZ_PARAMS)\n  File \"/home/app/.ansible/tmp/ansible-tmp-1568733667.5645123-182000990462949/AnsiballZ_docker_login.py\", line 120, in invoke_module\n    imp.load_module('__main__', mod, module, MOD_DESC)\n  File \"/home/app/containervol/python/python3/lib64/python3.7/imp.py\", line 234, in load_module\n    return load_source(name, filename, file)\n  File \"/home/app/containervol/python/python3/lib64/python3.7/imp.py\", line 169, in load_source\n    module = _exec(spec, sys.modules[name])\n  File \"<frozen importlib._bootstrap>\", line 630, in _exec\n  File \"<frozen importlib._bootstrap_external>\", line 728, in exec_module\n  File \"<frozen importlib._bootstrap>\", line 219, in _call_with_frames_removed\n  File \"/tmp/ansible_docker_login_payload_enwvm0yw/__main__.py\", line 354, in <module>\n  File \"/tmp/ansible_docker_login_payload_enwvm0yw/__main__.py\", line 343, in main\n  File \"/tmp/ansible_docker_login_payload_enwvm0yw/__main__.py\", line 171, in __init__\n  File \"/tmp/ansible_docker_login_payload_enwvm0yw/__main__.py\", line 227, in logout\nTypeError: 'in <string>' requires string as left operand, not bytes\n",
    "module_stdout": "",
    "msg": "MODULE FAILURE\nSee stdout/stderr for the exact error",
    "rc": 1
}

<!--- Paste verbatim command output between quotes -->
```paste below

```

#
#
from __future__ import absolute_import, division, print_function
__metaclass__ = type
ANSIBLE_METADATA = {'metadata_version': '1.1',
                    'status': ['preview'],
                    'supported_by': 'community'}
DOCUMENTATION = '''
---
module: docker_login
short_description: Log into a Docker registry.
version_added: "2.0"
description:
    - Provides functionality similar to the "docker login" command.
    - Authenticate with a docker registry and add the credentials to your local Docker config file. Adding the
      credentials to the config files allows future connections to the registry using tools such as Ansible's Docker
      modules, the Docker CLI and Docker SDK for Python without needing to provide credentials.
    - Running in check mode will perform the authentication without updating the config file.
options:
  registry_url:
    required: False
    description:
      - The registry URL.
    type: str
    default: "https://index.docker.io/v1/"
    aliases:
      - registry