Remove hard-coded host group
Remove hard-coded host group

A previous commit added a hard-coded host group to
rabbitmq-install.yml, instead of using the variable rabbitmq_host_group.
This commit updates rabbitmq-install.yml to use rabbitmq_host_group
instead.

Change-Id: I4c4f8d0b903cc56ed025b7223b52d3205d9c9d37

weezer/openstack-ansible,bunchc/openstack-ansible,bunchc/openstack-ansible,robb-romans/openstack-ansible,openstack/openstack-ansible,BjoernT/openstack-ansible,cfarquhar/openstack-ansible,os-cloud/os-ansible-deployment,BjoernT/os-ansible-deployment,cloudnull/os-ansible-deployment,stackforge/os-ansible-deployment,yanyao/openstack-ansible,Logan2211/openstack-ansible,weezer/openstack-ansible,yanyao/openstack-ansible,os-cloud/os-ansible-deployment,robb-romans/openstack-ansible,Logan2211/openstack-ansible,BjoernT/os-ansible-deployment,BjoernT/os-ansible-deployment,openstack/openstack-ansible,stackforge/os-ansible-deployment,cloudnull/os-ansible-deployment,cfarquhar/openstack-ansible,BjoernT/openstack-ansible