[gnome-shell/wip/sass] main: Fix unsetting of custom stylesheets

[Jakub Steiner <jimmac src gnome org>]

commit 9fc073d5b191a84b59c952c739fea4504aa103d7
Author: Florian Müllner <fmuellner gnome org>
Date:   Thu Nov 27 14:24:49 2014 +0000

    main: Fix unsetting of custom stylesheets
    
    Since moving to a GFile based API in commit 642bf2b7782819,
    setThemeStylesheet() no longer accepts %null to revert to
    the default theme. We should have some way to revert to the
    default and the least intrusive option is to return to the
    old behavior, so do that.

 js/ui/main.js |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/js/ui/main.js b/js/ui/main.js
index 9467d56..36d7591 100644
--- a/js/ui/main.js
+++ b/js/ui/main.js
@@ -271,7 +271,7 @@ function getThemeStylesheet() {
  * Set the theme CSS file that the shell will load
  */
 function setThemeStylesheet(cssStylesheet) {
-    _cssStylesheet = Gio.File.new_for_path(cssStylesheet);
+    _cssStylesheet = cssStylesheet ? Gio.File.new_for_path(cssStylesheet) : null;
 }
 
 /**