allow full ceph/rbd configuration to be done by chef

if cinder storage provider is rbd, and we are able to see the ceph fsid attribute in the chef environment, then we assume that we installed our ceph cluster using chef.  This means we can do all the necessary config for cinder to use rbd:

- install ceph packages and ceph.conf
- create cinder user
- create cinder pool
- drop in client keyring files