rbd: improve logging in getCloneDepth
rbd: improve logging in getCloneDepth

earlier if the depth check fails the
complete vol struct was getting logged,
this commits logs only the pool and image
name.

Signed-off-by: Madhu Rajanna <60fbf37a92c2a0908e31296d18dadbec5a4dae17@gmail.com>

ceph/ceph-csi,ceph/ceph-csi,ceph/ceph-csi,ceph/ceph-csi