[gdm] Don't use a null icon

[Ray Strode <halfline src gnome org>]

commit 6fc47b08425e8faae63367d00ffbbe73e05dc94b
Author: William Jon McCann <jmccann redhat com>
Date:   Thu Jan 13 23:34:56 2011 -0500

    Don't use a null icon
    
    https://bugzilla.gnome.org/show_bug.cgi?id=639284

 gui/simple-greeter/gdm-user-chooser-widget.c |    6 +++++-
 1 files changed, 5 insertions(+), 1 deletions(-)
---
diff --git a/gui/simple-greeter/gdm-user-chooser-widget.c b/gui/simple-greeter/gdm-user-chooser-widget.c
index 19a7922..8df255f 100644
--- a/gui/simple-greeter/gdm-user-chooser-widget.c
+++ b/gui/simple-greeter/gdm-user-chooser-widget.c
@@ -479,7 +479,11 @@ add_user (GdmUserChooserWidget *widget,
                 return;
         }
 
-        pixbuf = g_object_ref (widget->priv->stock_person_pixbuf);
+        if (widget->priv->stock_person_pixbuf != NULL) {
+                pixbuf = g_object_ref (widget->priv->stock_person_pixbuf);
+        } else {
+                pixbuf = NULL;
+        }
 
         tooltip = g_strdup_printf (_("Log in as %s"),
                                    gdm_user_get_user_name (user));