chrome: Make affectsStruts default to false

Since we only want it to be true for the panel, and nothing else.

https://bugzilla.gnome.org/show_bug.cgi?id=655813

js/ui/messageTray.js

@@ -1330,8 +1330,7 @@ MessageTray.prototype = {
         this._notificationRemoved = false;
         this._reNotifyAfterHideNotification = null;
 
-        Main.chrome.addActor(this.actor, { affectsStruts: false,
-                                           visibleInFullscreen: true });
+        Main.chrome.addActor(this.actor, { visibleInFullscreen: true });
         Main.chrome.trackActor(this._notificationBin);
         Main.chrome.trackActor(this._summaryBoxPointer.actor);