Update to match standard Go style.

Remove completely unused dial options, and
reorder a bit of code to match what real code would look like.

go/greeter_client/main.go

@@ -49,19 +49,18 @@ const (
 
 func main() {
 	// Set up a connection to the server.
-	var opts []grpc.DialOption
-	conn, err := grpc.Dial(address, opts...)
+	conn, err := grpc.Dial(address)
 	if err != nil {
 		log.Fatalf("did not connect: %v", err)
 	}
 	defer conn.Close()
+	c := pb.NewGreeterClient(conn)
 
 	// Contact the server and print out its response.
 	name := defaultName
 	if len(os.Args) > 1 {
 		name = os.Args[1]
 	}
-	c := pb.NewGreeterClient(conn)
 	r, err := c.SayHello(context.Background(), &pb.HelloRequest{Name: name})
 	if err != nil {
 		log.Fatalf("could not greet: %v", err)