Bug 42787 create volume with label (#46527)

* add None value to docker-version so it can be mocked in tests

lib/ansible/module_utils/docker_common.py

@@ -103,6 +103,8 @@ BYTE_SUFFIXES = ['B', 'KB', 'MB', 'GB', 'TB', 'PB']
 
 
 if not HAS_DOCKER_PY:
+    docker_version = None
+
     # No docker-py. Create a place holder client to allow
     # instantiation of AnsibleModule and proper error handing
     class Client(object):  # noqa: F811