Implement Ceph backend for Glance / Cinder / Nova

The new lib installs a full Ceph cluster. It can be managed
by the service init scripts. Ceph can also be installed in
standalone without any other components.
This implementation adds the auto-configuration for
the following services with Ceph:

* Glance
* Cinder
* Cinder backup
* Nova

To enable Ceph simply add: ENABLED_SERVICES+=,ceph to your localrc.
If you want to play with the Ceph replication, you can use the
CEPH_REPLICAS option and set a replica. This replica will be used for
every pools (Glance, Cinder, Cinder backup and Nova). The size of the
loopback disk used for Ceph can also be managed thanks to the
CEPH_LOOPBACK_DISK_SIZE option.

Going further pools, users and PGs are configurable as well. The
convention is <SERVICE_NAME_IN_CAPITAL>_CEPH_<OPTION> where services are
GLANCE, CINDER, NOVA, CINDER_BAK. Let's take the example of Cinder:

* CINDER_CEPH_POOL
* CINDER_CEPH_USER
* CINDER_CEPH_POOL_PG
* CINDER_CEPH_POOL_PGP

** Only works on Ubuntu Trusty, Fedora 19/20 or later **

Change-Id: Ifec850ba8e1e5263234ef428669150c76cfdb6ad
Implements: blueprint implement-ceph-backend
Signed-off-by: Sébastien Han <sebastien.han@enovance.com>
Merge "Implement Ceph backend for Glance / Cinder / Nova"