[nautilus] Don't inspect a null default app

[William Jon McCann <mccann src gnome org>]

commit c24efca6e81ebbb11ab2cafe3a7232447022d2f5
Author: William Jon McCann <jmccann redhat com>
Date:   Tue Aug 21 12:28:18 2012 -0400

    Don't inspect a null default app
    
    https://bugzilla.gnome.org/show_bug.cgi?id=682372

 .../nautilus-mime-application-chooser.c            |   10 +++++-----
 1 files changed, 5 insertions(+), 5 deletions(-)
---
diff --git a/libnautilus-private/nautilus-mime-application-chooser.c b/libnautilus-private/nautilus-mime-application-chooser.c
index f8a066f..adf2ed9 100644
--- a/libnautilus-private/nautilus-mime-application-chooser.c
+++ b/libnautilus-private/nautilus-mime-application-chooser.c
@@ -228,13 +228,13 @@ application_selected_cb (GtkAppChooserWidget *widget,
 	GAppInfo *default_app;
 
 	default_app = g_app_info_get_default_for_type (chooser->details->content_type, FALSE);
-	gtk_widget_set_sensitive (chooser->details->set_as_default_button,
-				  !g_app_info_equal (info, default_app));
-
+	if (default_app != NULL) {
+		gtk_widget_set_sensitive (chooser->details->set_as_default_button,
+					  !g_app_info_equal (info, default_app));
+		g_object_unref (default_app);
+	}
 	gtk_widget_set_sensitive (chooser->details->add_button,
 				  app_info_can_add (info, chooser->details->content_type));
-
-	g_object_unref (default_app);
 }
 
 static char *