test_rescued_vm_add_remove_security_group missing addCleanup

test_rescued_vm_add_remove_security_group on failure caused
other test cases fail.

Change-Id: I17ebb23f31bc10d669208b64a66e89fa415f96ac
diff --git a/tempest/api/compute/servers/test_server_rescue.py b/tempest/api/compute/servers/test_server_rescue.py
index 45fe5ac..20c5d7f 100644
--- a/tempest/api/compute/servers/test_server_rescue.py
+++ b/tempest/api/compute/servers/test_server_rescue.py
@@ -212,6 +212,7 @@
         self.servers_client.rescue_server(
             self.server_id, adminPass=self.password)
         self.servers_client.wait_for_server_status(self.server_id, 'RESCUE')
+        self.addCleanup(self._unrescue, self.server_id)
 
         # Add Security group
         resp, body = self.servers_client.add_security_group(self.server_id,
@@ -223,11 +224,6 @@
                                                                self.sg_name)
         self.assertEqual(202, resp.status)
 
-        # Unrescue the server
-        resp, body = self.servers_client.unrescue_server(self.server_id)
-        self.assertEqual(202, resp.status)
-        self.servers_client.wait_for_server_status(self.server_id, 'ACTIVE')
-
 
 class ServerRescueTestXML(ServerRescueTestJSON):
     _interface = 'xml'