This commit is based on how Nova got its configuration overrides
implemented.
An important thing here is support for setting multiple Cinder backends
(e.g. Ceph cluster + NFS) in the values.yaml. This was required as Cinder
accepts backend configurations only in [<backend_id>] sections in the
cinder.conf.
Please note that autogeneration of ceph.conf and
ceph.client.<rbd_user>.keyring works only for a backend named "rbd1".
In case you want to add another RBD backend, you need to mount those
files by yourself. Commit ehancing this is planned to follow shortly.
Change-Id: Ifb58a85300bbfbb9e63d6b3bfc2ad19a99d2c9d4
f0b92663d5