Update revision for rabbitmq

This commit updates the revision of rabbitmq to install for testing.

This revision was chosen for two reasons:

- later revisions remove the rabbitmq::server class
- later revisions do not support installing from your local distro (which
means you will likely get a version not tested with openstack)

Change-Id: Ic3fe0e672a84978b01bc7c9014dd701ecf2b0bde
Merge "Update revision for rabbitmq"