Some systems come with the /usr/lib/systemd/system directory. Some
others don't.
Ensuring with this commit that we always have this directory present,
otherwise the placing of the Docker unit file may fail and, in
consequence, the rest of the play.
Syntax change in playbooks and other small fixes
* Parameterisation of gpg args for yum
* Make the setup of vagrant user for docker optional
* Fix permissions on restarting the docker service
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1. Added some vars to defaults so that the end user can decide whether to use vagrant and docker-py
1. Updated syntax on tasks to follow `key: value` instead of `key=value` format, to make it easier
to track changes
1. Using an explicit become in the handler, since the task may not be run by root
Otherwise, when using this role in combination with some other calls to
Docker right after, the calls would fail as the handlers hadn't yet
kicked it and Docker wouldn't be running by then.
Carlos León
Bruce Becker