engine: VDS command to stop and delete geo-rep session

VDS command to stop and delete geo-replication session

Change-Id: Ib9f4a32783f2b119a56873b4c1290b10f8b208c8
Bug-Url: https://bugzilla.redhat.com/1125845
Signed-off-by: Sahina Bose <sabose@redhat.com>