Converts 'constraints' to local variable in order to fix desktop sharing issues(audio constraints were retained in global var and get desktop stream failed).

modules/RTC/RTCUtils.js

 //This should be uncommented when app.js supports require
 //var RTCBrowserType = require("../../service/RTC/RTCBrowserType.js");
 
-var constraints = {audio: false, video: false};
-
-function setResolutionConstraints(resolution, isAndroid)
+function setResolutionConstraints(constraints, resolution, isAndroid)
 {
     if (resolution && !constraints.video || isAndroid) {
         constraints.video = { mandatory: {}, optional: [] };// same behaviour as true
 }
 
 
-function setConstraints(um, resolution, bandwidth, fps, desktopStream, isAndroid)
+function getConstraints(um, resolution, bandwidth, fps, desktopStream, isAndroid)
 {
+    var constraints = {audio: false, video: false};
+
     if (um.indexOf('video') >= 0) {
         constraints.video = { mandatory: {}, optional: [] };// same behaviour as true
     }
         }
     }
 
-    setResolutionConstraints(resolution, isAndroid);
+    setResolutionConstraints(constraints, resolution, isAndroid);
 
     if (bandwidth) { // doesn't work currently, see webrtc issue 1846
         if (!constraints.video) constraints.video = {mandatory: {}, optional: []};//same behaviour as true
         if (!constraints.video) constraints.video = {mandatory: {}, optional: []};// same behaviour as true;
         constraints.video.mandatory.minFrameRate = fps;
     }
+
+    return constraints;
 }
 
 
     // Check if we are running on Android device
     var isAndroid = navigator.userAgent.indexOf('Android') != -1;
 
-    setConstraints(um, resolution, bandwidth, fps, desktopStream, isAndroid);
+    var constraints = getConstraints(
+        um, resolution, bandwidth, fps, desktopStream, isAndroid);
 
     var isFF = navigator.userAgent.toLowerCase().indexOf('firefox') > -1;
 
                     success_callback(stream);
                 },
                 function (error) {
-                    console.warn('Failed to get access to local media. Error ', error);
+                    console.warn('Failed to get access to local media. Error ',
+                        error, constraints);
                     if (failure_callback) {
                         failure_callback(error);
                     }