Fixes issue with desktop sharing when the user click Cancel on the popup window.

index.html

     <script src="libs/popover.js?v=1"></script><!-- bootstrap tooltip lib -->
     <script src="libs/toastr.js?v=1"></script><!-- notifications lib -->
     <script src="interface_config.js?v=5"></script>
-    <script src="libs/app.bundle.js?v=49"></script>
+    <script src="libs/app.bundle.js?v=50"></script>
     <script src="analytics.js?v=1"></script><!-- google analytics plugin -->
     <link rel="stylesheet" href="css/font.css?v=6"/>
     <link rel="stylesheet" href="css/toastr.css?v=1">

libs/app.bundle.js

     $("link[rel=chrome-webstore-item]").attr("href", getWebStoreInstallUrl());
 }
 
-function getSwitchStreamFailed(error) {
+function getVideoStreamFailed(error) {
     console.error("Failed to obtain the stream to switch to", error);
     switchInProgress = false;
     isUsingScreenStream = false;
     newStreamCreated(null);
 }
 
+function getDesktopStreamFailed(error) {
+    console.error("Failed to obtain the stream to switch to", error);
+    switchInProgress = false;
+}
+
 function streamSwitchDone() {
     switchInProgress = false;
     eventEmitter.emit(
                     );
                     newStreamCreated(stream);
                 },
-                getSwitchStreamFailed);
+                getDesktopStreamFailed);
         } else {
             // Disable screen stream
             APP.RTC.getUserMediaWithConstraints(
                     isUsingScreenStream = false;
                     newStreamCreated(stream);
                 },
-                getSwitchStreamFailed, config.resolution || '360'
+                getVideoStreamFailed, config.resolution || '360'
             );
         }
     }

modules/desktopsharing/desktopsharing.js

     $("link[rel=chrome-webstore-item]").attr("href", getWebStoreInstallUrl());
 }
 
-function getSwitchStreamFailed(error) {
+function getVideoStreamFailed(error) {
     console.error("Failed to obtain the stream to switch to", error);
     switchInProgress = false;
     isUsingScreenStream = false;
     newStreamCreated(null);
 }
 
+function getDesktopStreamFailed(error) {
+    console.error("Failed to obtain the stream to switch to", error);
+    switchInProgress = false;
+}
+
 function streamSwitchDone() {
     switchInProgress = false;
     eventEmitter.emit(
                     );
                     newStreamCreated(stream);
                 },
-                getSwitchStreamFailed);
+                getDesktopStreamFailed);
         } else {
             // Disable screen stream
             APP.RTC.getUserMediaWithConstraints(
                     isUsingScreenStream = false;
                     newStreamCreated(stream);
                 },
-                getSwitchStreamFailed, config.resolution || '360'
+                getVideoStreamFailed, config.resolution || '360'
             );
         }
     }