CA-130987: Forward any exceptions thrown inside _snapshot

Signed-off-by: Vineeth Raveendran <vineeth.thampi@citrix.com>
Reviewed-by: Chandrika Srinivasan <chandrika.srinivasan@citrix.com>

GitHub: closes #169 on xapi-project/sm

drivers/LVHDSR.py

@@ -1590,7 +1590,7 @@ def _do_snapshot(self, sr_uuid, vdi_uuid, snapType, cloneOp=False, secondary=Non
             except Exception, e2:
                 util.SMlog('WARNING: failed to clean up failed snapshot: '
                         '%s (error ignored)' % e2)
-                raise e1
+            raise e1
         blktap2.VDI.tap_unpause(self.session, sr_uuid, vdi_uuid, secondary)
         return snapResult