ceph-nfs: fix internal ganesha deployment

ceph-nfs: fix internal ganesha deployment

Since ea2b654d9 we're not running the rados command from the monitor
nodes but from the ganesha node. Unfortunately we don't have the
required keyring on that node to run the rados command as we don't
import the right keyring.
This commit restores the workflow for internal ganesha deployment like
before ea2b654d9 but keeps the rados commands from the ganesha node for
external deployment until we have a better design.

Signed-off-by: Dimitri Savineau <dsavinea@redhat.com>