Remove dependency on @google-cloud/common (#165)

Author: JustinBeckwith

dialogflow/detect.js

@@ -15,7 +15,7 @@
 
 'use strict';
 
-const common = require('@google-cloud/common');
+const util = require('util');
 const fs = require('fs');
 const structjson = require('./structjson.js');
 const pump = require('pump');
@@ -145,7 +145,7 @@ function detectAudioIntent(
   const sessionPath = sessionClient.sessionPath(projectId, sessionId);
 
   // Read the content of the audio file and send it as part of the request.
-  const readFile = common.util.promisify(fs.readFile, {singular: true});
+  const readFile = util.promisify(fs.readFile);
   readFile(filename)
     .then(inputAudio => {
       // The audio query request

dialogflow/detect.v2beta1.js

@@ -17,7 +17,7 @@
 
 const projectId = process.env.GCLOUD_PROJECT;
 const sessionId = require('uuid/v1')();
-const common = require('@google-cloud/common');
+const util = require('util');
 const structjson = require('./structjson.js');
 
 function createKnowledgeBase(projectId, displayName) {
@@ -530,7 +530,7 @@ function detectIntentwithModelSelection(
   // Define session path
   const sessionPath = sessionClient.sessionPath(projectId, sessionId);
   // Read the content of the audio file and send it as part of the request.
-  const readFile = common.util.promisify(fs.readFile, {singular: true});
+  const readFile = util.promisify(fs.readFile);
   readFile(audioFilePath)
     .then(inputAudio => {
       // The audio query request

dialogflow/package.json

@@ -12,7 +12,6 @@
     "test": "ava system-test"
   },
   "dependencies": {
-    "@google-cloud/common": "^0.20.0",
     "dialogflow": "0.6.0",
     "grpc": "^1.4.1",
     "pump": "^3.0.0",