SEBA-397 Add support for mib upload of TCONT MEs.

Also update openolt.proto to match voltha master (compatible with voltha 1.6)

Change-Id: Ib7ac1a2cdea6e67c4e59fa25819790973d4630e6
diff --git a/core/grpc_service.go b/core/grpc_service.go
index 2175a75..05a3d85 100644
--- a/core/grpc_service.go
+++ b/core/grpc_service.go
@@ -89,6 +89,16 @@
 	return new(openolt.Empty), nil
 }
 
+func (s *Server) CreateTconts(c context.Context, tconts *openolt.Tconts) (*openolt.Empty, error) {
+	logger.Debug("OLT receives CreateTconts()")
+	return new(openolt.Empty), nil
+}
+
+func (s *Server) RemoveTconts(c context.Context, tconts *openolt.Tconts) (*openolt.Empty, error) {
+	logger.Debug("OLT receives RemoveTconts()")
+	return new(openolt.Empty), nil
+}
+
 func (s *Server) DeactivateOnu(c context.Context, onu *openolt.Onu) (*openolt.Empty, error) {
 	logger.Debug("OLT receives DeactivateONU()")
 	return new(openolt.Empty), nil