Update custom vars plugin for Ansible 1.7+

With the introduction of Ansbile 1.7, our var plugin broke due to
incompatible changes upstream. Update the plugin so that we can make
use of the new Ansible releases.

!version-patch
Update rabbitmq tasks for ansible 1.7+

In recent versions of Ansible, they no longer support some jinja
patterns in tasks. Specifically, jinja may not *add* arguments to a
module.  Therefore, break each of these tasks into 2 separate cases
handled by the "when" conditional.

!version-patch
bootstrap: fix locale command

also added the locale to the testenv pre-deploy.yml,
machines spun up by test was giving locale errors in
shell.

there's a few items in the two that should
be DRYed up a little.
Merge pull request #516 from craigtracey/vars-plugin-update

Update custom vars plugin for Ansible 1.7+
Merge pull request #531 from craigtracey/rabbit-ansible

Update rabbitmq tasks for ansible 1.7+
de-variablize locale
Merge pull request #528 from blueboxgroup/fix/locale

bootstrap: fix locale command
Update requirements

Updating ansible to 1.7.2