[gnome-shell] main: Remove unused 'background' property

[Jasper St. Pierre <jstpierre src gnome org>]

commit dc0ea3a248fef18e4380728f61ba04800d93e972
Author: Jasper St. Pierre <jstpierre mecheye net>
Date:   Fri Dec 21 07:41:10 2012 -0500

    main: Remove unused 'background' property

 js/ui/main.js |    2 --
 1 files changed, 0 insertions(+), 2 deletions(-)
---
diff --git a/js/ui/main.js b/js/ui/main.js
index b907eb9..f8235f6 100644
--- a/js/ui/main.js
+++ b/js/ui/main.js
@@ -81,8 +81,6 @@ let _defaultCssStylesheet = null;
 let _cssStylesheet = null;
 let _overridesSettings = null;
 
-let background = null;
-
 function _sessionUpdated() {
     wm.setCustomKeybindingHandler('panel-main-menu',
                                   KeybindingMode.NORMAL |