Add support for latest puppetlabs-rabbitmq

(Patch related (copy/paste) to http://git.io/T9zQHg from Michael)

This patch adds a new paramter to the rabbitmq class
that allows a user to specify the class name. This allows
selection of 'rabbitmq::server' - the old name, or 'rabbitmq' -
the new name changed during the recent rewrite of the
puppetlabs-rabbitmq module.

Change-Id: I3dfb05456caf7af6b00b58ab86d413d4d3b85c5e
Merge "Add support for latest puppetlabs-rabbitmq"