messageTray: Don't exit out early if we have a left timeout

Otherwise, we won't mark the pointer as hovering on the notification.

https://bugzilla.gnome.org/show_bug.cgi?id=731118

js/ui/messageTray.js

@@ -2283,7 +2283,6 @@ const MessageTray = new Lang.Class({
                 this._notificationLeftTimeoutId = 0;
                 this._notificationLeftMouseX = -1;
                 this._notificationLeftMouseY = -1;
-                return;
             }
 
             if (this._showNotificationMouseX >= 0) {
@@ -2301,6 +2300,7 @@ const MessageTray = new Lang.Class({
                     return;
                 }
             }
+
             this._pointerInNotification = true;
             this._updateState();
         } else {