cleanup: Use method syntax

Modern javascript has a short-hand for function properties, embrace
it for better readability and to prepare for an eventual port to
ES6 classes.

https://gitlab.gnome.org/GNOME/gnome-shell/merge_requests/23

js/ui/main.js

@@ -686,7 +686,7 @@ var RestartMessage = new Lang.Class({
     Name: 'RestartMessage',
     Extends: ModalDialog.ModalDialog,
 
-    _init : function(message) {
+    _init(message) {
         this.parent({ shellReactive: true,
                       styleClass: 'restart-message headline',
                       shouldFadeIn: false,