[gthumb] contact sheet: fixed warning

[Paolo Bacchilega <paobac src gnome org>]

commit 832d8599926909d0142a5bbaa300220b584a0732
Author: Paolo Bacchilega <paobac src gnome org>
Date:   Tue Nov 26 18:41:41 2013 +0100

    contact sheet: fixed warning

 extensions/contact_sheet/dlg-contact-sheet.c |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)
---
diff --git a/extensions/contact_sheet/dlg-contact-sheet.c b/extensions/contact_sheet/dlg-contact-sheet.c
index bd397c5..494571e 100644
--- a/extensions/contact_sheet/dlg-contact-sheet.c
+++ b/extensions/contact_sheet/dlg-contact-sheet.c
@@ -472,7 +472,7 @@ theme_dialog_response_cb (GtkDialog *dialog,
        GError               *error = NULL;
 
        if (response_id == GTK_RESPONSE_CANCEL) {
-               gtk_widget_destroy (dialog);
+               gtk_widget_destroy (GTK_WIDGET (dialog));
                return;
        }
 
@@ -558,7 +558,7 @@ theme_dialog_response_cb (GtkDialog *dialog,
        gtk_tree_path_free (path);
        g_object_unref (preview);
 
-       gtk_widget_destroy (dialog);
+       gtk_widget_destroy (GTK_WIDGET (dialog));
 }