[gnome-shell] loginDialog: don't try to stop work spinner if it's already gone

[Ray Strode <halfline src gnome org>]

commit 07c0105c8392b43bc07b5ddf5c5aced9780ef3f7
Author: Ray Strode <rstrode redhat com>
Date:   Wed Feb 6 14:36:37 2013 -0500

    loginDialog: don't try to stop work spinner if it's already gone
    
    This can happen if the dialog gets reset at the wrong moment.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=693757

 js/gdm/loginDialog.js |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)
---
diff --git a/js/gdm/loginDialog.js b/js/gdm/loginDialog.js
index d2b93ba..d41b520 100644
--- a/js/gdm/loginDialog.js
+++ b/js/gdm/loginDialog.js
@@ -1063,7 +1063,8 @@ const LoginDialog = new Lang.Class({
                                transition: 'linear',
                                onCompleteScope: this,
                                onComplete: function() {
-                                   this._workSpinner.stop();
+                                   if (this._workSpinner)
+                                       this._workSpinner.stop();
                                }
                              });
         }