The JSON the Docker API returns includes the container's ENTRYPOINT value (if it has one) with the 'Command' value. So instead of checking if `container['Command'] == module.params['command']`, we just check that `container['Command'].endswith(module.params['command'])` so the entrypoint won't affect a container being properly classified as matching the module params or not.
Also I refactored a super-long `if` statement into some temporary variables - I did it to help me figure out what was going wrong, and then it makes the code more readable so I kept it.
The new present state just makes sure that a container exists, not that
it's running, although it get started one creation.
This is very useful for data volumes. This also changes the old
present, now running (default) state to only create the container if
it's not found, otherwise it just get started.
See also discussion on mailinglist:
https://groups.google.com/forum/#!topic/ansible-devel/jB84gdhPzLQ
This closes#6395
When using repositories other than the main one at docker.io, the image name contains the repo name (which itself contains ":" as a separator between domain and port). We don't really care about it here, so just get rid of it before looking at the image name.
