Add upgrade support for ceph-mon service
Add upgrade support for ceph-mon service

Initial support for a rolling upgrade of ceph-mon services which
happens before the OpenStack services are upgraded.

Change-Id: Ifaebbe2ae884bd899cdc6f1c288274e5838792a6
Partially-Implements: blueprint overcloud-upgrades-per-service

openstack/tripleo-heat-templates,dprince/tripleo-heat-templates,openstack/tripleo-heat-templates,dprince/tripleo-heat-templates