allow full ceph/rbd configuration to be done by chef

if glance image store 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 glance to use rbd:

- install ceph packages and ceph.conf
- create glance user
- create glance pool
- drop in client keyring files