Update greeter_client.js

Switched declaration order

examples/node/static_codegen/greeter_client.js

@@ -39,13 +39,13 @@ var grpc = require('grpc');
 function main() {
   var client = new services.GreeterClient('localhost:50051',
                                           grpc.credentials.createInsecure());
+  var request = new messages.HelloRequest();
   var user;
   if (process.argv.length >= 3) {
     user = process.argv[2];
   } else {
     user = 'world';
   }
-  var request = new messages.HelloRequest();
   request.setName(user);
   client.sayHello(request, function(err, response) {
     console.log('Greeting:', response.getMessage());