Port with_ loop variable syntax to Ansbile 2

Migrate to full variable syntax in with_ loop
instead of bare variables for:
- ceph
- ceilometer
- glance
- heat
- horizon
- keystone
- mariadb
- memcached
- neutron
- nova
- rabbitmq

Change-Id: Ib925b4ecea47ac758a77739c9c7e140f06933b08
Partial-Implements: blueprint ansible2