Update ProtoBuf 3 & gRPC

- Protocol Buffers: 3.0.0
- gRPC: 1.0.0-pre2

Change-Id: Ic80d3f660d4a0aa37a99d4e6d4dc45e0b70b073b
diff --git a/apps/kafka-integration/core/src/main/java/org/onosproject/kafkaintegration/converter/LinkEventConverter.java b/apps/kafka-integration/core/src/main/java/org/onosproject/kafkaintegration/converter/LinkEventConverter.java
index febe020..913d0e5 100644
--- a/apps/kafka-integration/core/src/main/java/org/onosproject/kafkaintegration/converter/LinkEventConverter.java
+++ b/apps/kafka-integration/core/src/main/java/org/onosproject/kafkaintegration/converter/LinkEventConverter.java
@@ -25,7 +25,7 @@
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
-import com.google.protobuf.GeneratedMessage;
+import com.google.protobuf.GeneratedMessageV3;
 
 /**
  * Converts for ONOS Link event message to protobuf format.
@@ -35,7 +35,7 @@
     private final Logger log = LoggerFactory.getLogger(getClass());
 
     @Override
-    public GeneratedMessage convertToProtoMessage(Event<?, ?> event) {
+    public GeneratedMessageV3 convertToProtoMessage(Event<?, ?> event) {
 
         LinkEvent linkEvent = (LinkEvent) event;