Updated to integrate with vagrant cleaner

* Configured vagrant provision to execute as a role so defaults are properly
  loaded.
* Moved test vars to Vagrantfile explicit loading
* No longer need to ignore `vagrant_ansible_inventory_default` with a newer
  version of Vagrant.
Ok, but weirdly when showed on screen I get a double quote and not only one:

    GATHERING FACTS *************************************************************** 
    ok: [vagrantup]

    TASK: [rabbitmq | add the official rabbitmq repository''s key] **************** 
    ok: [vagrantup]

When I look at the [YAML spec](http://yaml.org/spec/current.html#id2517668) I only see that `\` is the escaping character, where did you see `'` was?

Surrounding the whole strings with `"` fix the coloring issue (At least in emacs the syntax colouring is right with that. Weirdly in VIM I did not get this syntax coloration error).