Currently, TripleO does not support to create Compute roles
using different Ceph pools as Nova Ephemeral backends.
An admin should be allowed to have groups of compute nodes
using different Ceph's Ephemeral pools improving
availability, reliability and performance.
The change is straight forward adding the
role_specific tag to the parameter NovaRbdPoolName.
Closes-Bug: 1821039
Change-Id: I7c1ac7c0d3a987c8c9c1e070ea773875aa684d88