Change Rabbit_Hosts From Cluster VIP to a List of Real IPs

Addresses bug:

  https://bugs.launchpad.net/openstack-cisco/+bug/1233369

We have expirneced inconsistent behavior of OS service stability
when load-balancing RPC traffic.  This change will allow Cinder,
Quantum and Nova to use a list of controller node hostnames to
provide HA of RPC traffic.