Adjust mcollective::middleware::rabbitmq to handle installing the stomp plugin correctly.

Currently the rabbitmq middleware class leaves rabbitmq configured to use stomp but running a version configured prior to stomp being configured and requiring a manual restart of the service.

The dependency rabbitmq module should already handle installing the stomp plugin and properly setting the necessary resource ordering to ensure we are left in a functional state but has minor errors being addressed in https://github.com/puppetlabs/puppetlabs-rabbitmq/pull/206 and https://github.com/puppetlabs/puppetlabs-rabbitmq/pull/205.