ofagent import bugfix

Change-Id: I0e14fa9ba7af909ae3f969497130cef850545504
diff --git a/ofagent/grpc_client.py b/ofagent/grpc_client.py
index 1214507..6d01015 100644
--- a/ofagent/grpc_client.py
+++ b/ofagent/grpc_client.py
@@ -28,7 +28,8 @@
 from twisted.internet.defer import inlineCallbacks, returnValue, DeferredQueue
 
 from protos.voltha_pb2 import ID, VolthaLocalServiceStub, FlowTableUpdate, \
-    FlowGroupTableUpdate, PacketOut, LogicalPortId
+    FlowGroupTableUpdate, PacketOut
+from protos.logical_device_pb2 import LogicalPortId
 from google.protobuf import empty_pb2