ceph: do not log an error if no clusters
ceph: do not log an error if no clusters

If the list of cluster is empty there is no need to report an error in
the logs.

Signed-off-by: Sébastien Han <62d754cc350e84d3b1c32ae79f976f5348e74a40@redhat.com>

rook/nfs,rook/rook,rook/rook,rook/nfs,rook/rook,rook/nfs,rook/rook,rook/rook