Added default as unmarshal, so old scripts do not break

Author: kkumara3

examples/telemetry_collector.py

@@ -19,6 +19,8 @@ def print_connectivity(connectivity):
 client.connectivityhandler(print_connectivity)
 # Iterate over subscription recvs.
 for segment in client.getsubscription(subscription_id, unmarshal=True):
+    # unmarshal is an optional argument, default is unmarshal = True
+    # If unmarshal is false, out is in gpb k/v
 	recv_count += 1
 	print json.dumps(segment, indent=4, separators=(',', ': '))
 	print 'End Telemetry Segment'

lib/cisco_grpc_client.py

@@ -86,7 +86,7 @@ def getconfig(self, path):
             err += response.errors
         return err, objects
 
-    def getsubscription(self, sub_id, unmarshal):
+    def getsubscription(self, sub_id, unmarshal=True):
         """Telemetry subscription function
             :param sub_id: Subscription ID
             :type: string