Small bug fix in producer.py

Signed-off-by: Helena McGough <helena.mcgough@intel.com>
diff --git a/core/message_bus/producer.py b/core/message_bus/producer.py
index f5abce2..1b0de7a 100644
--- a/core/message_bus/producer.py
+++ b/core/message_bus/producer.py
@@ -65,7 +65,7 @@
 
     def publish(self, key, value, topic=None):
         try:
-            future = self.producer.send(key, value, topic)
+            future = self.producer.send(topic=topic, key=key, value=value)
             self.producer.flush()
         except Exception:
             logging.exception("Error publishing to {} topic." .format(topic))