Fix: resolve NPE caused by non-existence of IP protocol

Change-Id: I8f2233637986089b9347da03221db2852faa7fe7
diff --git a/apps/openstacktelemetry/app/src/main/java/org/onosproject/openstacktelemetry/impl/KafkaTelemetryManager.java b/apps/openstacktelemetry/app/src/main/java/org/onosproject/openstacktelemetry/impl/KafkaTelemetryManager.java
index 8d6f62f..d1de54a 100644
--- a/apps/openstacktelemetry/app/src/main/java/org/onosproject/openstacktelemetry/impl/KafkaTelemetryManager.java
+++ b/apps/openstacktelemetry/app/src/main/java/org/onosproject/openstacktelemetry/impl/KafkaTelemetryManager.java
@@ -128,6 +128,7 @@
             return null;
         }
 
+        log.debug("Send telemetry record to kafka server...");
         return producer.send(record);
     }