Bug Fixes for Kafka Application(patchset #2)

1. Coding Errors in both the Converters
2. Pom file needs an import for com.google.protobuf
3. Port Object can be null in DeviceEvent. Added a check in the DeviceEventConverter

Change-Id: I28fe7e388b31bec7971b4ab1f431a3520162b53e
diff --git a/apps/kafka-integration/app/pom.xml b/apps/kafka-integration/app/pom.xml
index 20b9427..1dafb0d 100644
--- a/apps/kafka-integration/app/pom.xml
+++ b/apps/kafka-integration/app/pom.xml
@@ -167,7 +167,8 @@
                         org.onlab.packet.*,
                         org.onosproject.*,
                         org.onlab.util.*,
-                        com.google.common.*
+                        com.google.common.*,
+                        com.google.protobuf.*
                     </Import-Package>
                     <Web-ContextPath>${web.context}</Web-ContextPath>
                 </instructions>