title: Dialogflow handles one webhook correctly but refuses another
body: <p>I'm currently using Glitch's(Glitch.com) node.js to connect Dialogflow to code and I'm running into a problem. As you can see below; I have two intents I'm trying to pass values to, characterHandler and openHandler. </p>
  
  <p>Now the weird thing is that it <strong>does</strong> execute the web hook correctly if I trigger the intent on Dialogflow corresponding to "characterHandler", but it returns "UnhandledPromiseRejectionWarning: Error: no matching intent handler for: null" in the console and fails while triggering "openHandler" and I have no clue why. </p>
  
  <p>Does anyone know what I'm doing wrong?</p>
  
  <pre><code>'use strict';
  
  process.env.DEBUG = 'actions-on-google:*';
  
  const express = require('express');
  const bodyParser = require('body-parser');
  const request = require("request");
  const { DialogflowApp } = require('actions-on-google');
  const Map = require('es6-map');
  const app = express();
  
  app.use(bodyParser.json());
  
  
  let characters = ['The Pied Piper', 'Red Riding Hood', 'The Big Bad Wolf'];
  
  // [START Action]
  app.post('/', function (request, response) {
    const assistant = new DialogflowApp({request, response});
    console.log('Request headers: ' + JSON.stringify(request.headers));
    console.log('Request body: ' + JSON.stringify(request.body));
  
  const CHARACTERS = 'story.characters';
  const OPENINGTIMES = 'openingTimes';
  
    function characterHandler (assistant) {
      let responseText = "How about";
  
      responseText = characters[Math.floor(Math.random() * characters.length)];
      assistant.tell(responseText);
    }
  
    function openHandler (assistant) {
      assistant.tell('This attraction is currently full');
    }
  
    const actionMap = new Map();
    actionMap.set(CHARACTERS, characterHandler);
    actionMap.set(OPENINGTIMES, openHandler);
  
    assistant.handleRequest(actionMap);
  
  });
  // [END Action]
  
  // Renders the homepage
  app.get('/', function (req, res) {
    res.writeHead(200, {'Content-Type': 'text/html'});
    res.write('');
    res.end();
  });
  
  if (module === require.main) {
    // [START server]
    // Start the server
    let server = app.listen(process.env.PORT || 3000, function () {
      let port = server.address().port;
      console.log('App listening on port %s', port);
    });
    // [END server]
  }
  
  module.exports = app;
  </code></pre>