[gnome-shell] windowManager: Replace deprecated g_settings_list_keys()

[Florian Müllner <fmuellner src gnome org>]

commit 530193a3a224e35d8f0799c0a83dfdb6fbcdce52
Author: Florian Müllner <fmuellner gnome org>
Date:   Fri Jun 19 13:58:41 2015 +0200

    windowManager: Replace deprecated g_settings_list_keys()

 js/ui/windowManager.js |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/js/ui/windowManager.js b/js/ui/windowManager.js
index ecf6051..5a86d5a 100644
--- a/js/ui/windowManager.js
+++ b/js/ui/windowManager.js
@@ -217,7 +217,7 @@ const WorkspaceTracker = new Lang.Class({
 
     _getWorkspaceSettings: function() {
         let settings = global.get_overrides_settings();
-        if (settings.list_keys().indexOf('dynamic-workspaces') > -1)
+        if (settings.settings_schema.list_keys().indexOf('dynamic-workspaces') > -1)
             return settings;
         return new Gio.Settings({ schema_id: 'org.gnome.mutter' });
     },