Removes unnecessary error dialog when desktop sharing is started before the conference.

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=26"></script>
+    <script src="libs/app.bundle.js?v=27"></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">

modules/xmpp/xmpp.js

             connection.jingle.activecall.switchStreams(stream, oldStream, callback);
         } else {
             // We are done immediately
-            console.error("No conference handler");
-            APP.UI.messageHandler.showError("dialog.error",
-                "dialog.unableToSwitch");
+            console.warn("No conference handler or conference not started yet");
             callback();
         }
     },