Time-stamp added and renamed heartbeat

Change-Id: I7f38752aa83572bc6b6b93093546e0fdf47763f5
diff --git a/kafka/kafka-consumer.py b/kafka/kafka-consumer.py
index 3f405d8..0b45f6f 100644
--- a/kafka/kafka-consumer.py
+++ b/kafka/kafka-consumer.py
@@ -20,7 +20,7 @@
 
 
 class ConsumerExample(object):
-    def __init__(self, consul_endpoint, topic="heartbeat.voltha", runtime=60):
+    def __init__(self, consul_endpoint, topic="voltha.heartbeat", runtime=60):
         self.topic = topic
         self.runtime = runtime
         self.kafka_endpoint = get_endpoint_from_consul(consul_endpoint,
@@ -105,7 +105,7 @@
 
     parser.add_argument("-t", "--topic",
                         help="topic to listen from",
-                        default="heartbeat.voltha")
+                        default="voltha.heartbeat")
 
     parser.add_argument("-r", "--runtime",
                         help="total runtime",