tray: fix so that trayicons using symbolic icons get the right colors

The tray protocol only allows setting a single set of colors for all
symbolic trayicons; we use the message-tray's theme node to set that.

https://bugzilla.gnome.org/show_bug.cgi?id=641060

js/ui/main.js

@@ -144,7 +144,9 @@ function start() {
     notificationDaemon = new NotificationDaemon.NotificationDaemon();
     windowAttentionHandler = new WindowAttentionHandler.WindowAttentionHandler();
     telepathyClient = new TelepathyClient.Client();
+
     panel.startStatusArea();
+    statusIconDispatcher.start(messageTray.actor);
 
     ctrlAltTabManager = new CtrlAltTab.CtrlAltTabManager();
     ctrlAltTabManager.addGroup(panel.actor, _("Panel"), 'gnome-panel');