This adds the required functionality to
call the go-ceph API's for the rbd
volume group.

Signed-off-by: Madhu Rajanna <[email protected]>

implementing GetMirrorSource in manager
to return volume or the volumegroup based
on the replication source, if replication
source is nil return the volume details
for backward compatibility.

Signed-off-by: Madhu Rajanna <[email protected]>

This is temporary test only
commit and not suitable for
review.

Signed-off-by: Madhu Rajanna <[email protected]>

This is extra commit will be dropped

Signed-off-by: Madhu Rajanna <[email protected]>