Provide options to pass in Ceph cluster-id

This commit provides the option to pass in Ceph cluster-id instead
of a MON list from the storage class.

This helps in moving towards a stateless CSI implementation.

Tested the following,
- PV provisioning and staging using cluster-id in storage class
- PV provisioning and staging using MON list in storage class

Did not test,
- snapshot operations in either forms of the storage class

Signed-off-by: ShyamsundarR <srangana@redhat.com>

pkg/rbd/rbd_attach.go

@@ -280,7 +280,7 @@ func createPath(volOpt *rbdVolume, userID string, creds map[string]string) (stri
 	}
 
 	klog.V(5).Infof("rbd: map mon %s", mon)
-	key, err := getRBDKey(userID, creds)
+	key, err := getRBDKey(volOpt.FsID, userID, creds)
 	if err != nil {
 		return "", err
 	}