Update gRPC

- Update gRPC and it's dependencies to 0.13.2
- Use pre-defined default port if not specified by URI
- Cosmetic fixes

Change-Id: Iac8c3ba4c6fe1b5925ea8832e61d313adfad6f71
diff --git a/incubator/rpc-grpc/src/main/java/org/onosproject/incubator/rpc/grpc/LinkProviderServiceServerProxy.java b/incubator/rpc-grpc/src/main/java/org/onosproject/incubator/rpc/grpc/LinkProviderServiceServerProxy.java
index 80322dc..bf35ed2 100644
--- a/incubator/rpc-grpc/src/main/java/org/onosproject/incubator/rpc/grpc/LinkProviderServiceServerProxy.java
+++ b/incubator/rpc-grpc/src/main/java/org/onosproject/incubator/rpc/grpc/LinkProviderServiceServerProxy.java
@@ -51,6 +51,9 @@
 
     private final GrpcRemoteServiceServer server;
 
+    // TODO implement aging mechanism to automatically remove
+    // stale links reported by dead client, etc.
+
     LinkProviderServiceServerProxy(GrpcRemoteServiceServer server) {
         this.server = checkNotNull(server);
     }