Pass Docker daemon connection params from inventory to connection plugin (#157)

* Move variable handling to doc fragment, and make them known to module_utils.

* Pass Daemon connection options to connection plugin.

* Add changelog fragment.

* Fix syntax error.

* Forgot 'options:'.

plugins/module_utils/common.py

@@ -96,6 +96,12 @@ DOCKER_COMMON_ARGS = dict(
     debug=dict(type='bool', default=False)
 )
 
+DOCKER_COMMON_ARGS_VARS = dict([
+    [option_name, 'ansible_docker_%s' % option_name]
+    for option_name in DOCKER_COMMON_ARGS
+    if option_name != 'debug'
+])
+
 DOCKER_MUTUALLY_EXCLUSIVE = []
 
 DOCKER_REQUIRED_TOGETHER = [