merged 7c4add53b497798e7fd7b204f28e41ab409bdbb7 from golang/protobuf.…

… protoc-gen-go: remove deprecated function in grpc (#426)

protoc-gen-gogo/grpc/grpc.go

@@ -306,15 +306,15 @@ func (g *grpc) generateClientMethod(servName, fullServName, serviceDescVar strin
 	if !method.GetServerStreaming() && !method.GetClientStreaming() {
 		g.P("out := new(", outType, ")")
 		// TODO: Pass descExpr to Invoke.
-		g.P("err := ", grpcPkg, `.Invoke(ctx, "`, sname, `", in, out, c.cc, opts...)`)
+		g.P(`err := c.cc.Invoke(ctx, "`, sname, `", in, out, opts...)`)
 		g.P("if err != nil { return nil, err }")
 		g.P("return out, nil")
 		g.P("}")
 		g.P()
 		return
 	}
 	streamType := unexport(servName) + methName + "Client"
-	g.P("stream, err := ", grpcPkg, ".NewClientStream(ctx, ", descExpr, `, c.cc, "`, sname, `", opts...)`)
+	g.P("stream, err := c.cc.NewStream(ctx, ", descExpr, `, "`, sname, `", opts...)`)
 	g.P("if err != nil { return nil, err }")
 	g.P("x := &", streamType, "{stream}")
 	if !method.GetClientStreaming() {