Add 'bc' as a dependancy to Galera

Change-Id: I8d0565fa9dca949592957c62c419163d1d2a7dcf
Closes-bug: 1285089
Set rabbit_hosts to a list of controllers

Connecting to RabbitMQ via HAProxy results in hung AMQP sessions after
controller failover or VIP move. To work around this problem, OpenStack
services have to be configured to connect directly to RabbitMQ services
on controllers nodes via rabbit_hosts variable, which makes impl_kombu
cycle through the listed hosts when attempting to reconnect. On
controller nodes, preference is given to the local RabbitMQ service on
the same controller node.

AMQP client configuration for all OpenStack components is centralized in
osnailyfacter and propagated through Puppet classes in a consistent
manner.

Following components are excluded in this fix and will require separate
patches:

 * Neutron uses sanitize_neutron_config() function instead of Puppet
   class parameters for configuration

 * Murano has its own RPC implementation that is inconsistent with the
   rest of the OpenStack

Change-Id: Ib839032b2f1aa820b4afc64b0a9badf13414d488
Partial-bug: #1285449
Set rabbit_hosts to a list of controllers for Neutron

It's addition to the https://review.openstack.org/#/c/77409
This commit shouldn't be merged before https://review.openstack.org/#/c/77409
It also can fail tests without it.

Change-Id: I3f816ce9bb98b42b80794c28fd9fc21e55e4084b
Partial-bug: #1285449