Skip forming cluster if ONOS cluster was already formed.

Change-Id: I60b18cc4dd756e94d934641b99ee524dff9d7d1e
diff --git a/src/test/cluster/clusterTest.py b/src/test/cluster/clusterTest.py
index 080f547..11a398f 100644
--- a/src/test/cluster/clusterTest.py
+++ b/src/test/cluster/clusterTest.py
@@ -363,7 +363,7 @@
             index = num % ctlr_len
             #index = random.randrange(0, ctlr_len)
             controller = onos_map[controllers[index]] if next_controller is None else next_controller
-            log.info('Restarting Controller %s' %controller)
+            log.info('ITERATION: %d. Restarting Controller %s' %(num + 1, controller))
             try:
                 cord_test_onos_restart(node = controller)
                 time.sleep(30)