Remove the deprecated options rabbit_host, rabbit_port, rabbit_hosts,
rabbit_userid, rabbit_password and rabbit_virtual_host [1].
All modules should support this change already or I have open patches
that fixes it.
Added a proper prelude notification that the functionality that
changed rabbit_ha_queues to true automatically if rabbit_hosts was
used is now removed so it has to be set explicitly.
[1] https://review.openstack.org/#/c/599912/
Depends-On: https://review.openstack.org/#/c/612190/
Depends-On: https://review.openstack.org/#/c/612191/
Change-Id: Ie151e1857e6e951c676986c6b2778db0d0a52819