[gthumb] fixed help button in preferences window, bug 671290

[Michael J. Chudobiak <mjc src gnome org>]

commit 964c6a87a8d8eb5cf3f528ef5369ded9fc236dea
Author: Michael J. Chudobiak <mjc avtechpulse com>
Date:   Wed Mar 21 08:55:33 2012 -0400

    fixed help button in preferences window, bug 671290

 gthumb/dlg-preferences.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/gthumb/dlg-preferences.c b/gthumb/dlg-preferences.c
index 542535c..518e9af 100644
--- a/gthumb/dlg-preferences.c
+++ b/gthumb/dlg-preferences.c
@@ -111,7 +111,7 @@ static void
 help_button_clicked_cb (GtkWidget  *widget,
 			DialogData *data)
 {
-	show_help_dialog (GTK_WINDOW (data->dialog), "preferences");
+	show_help_dialog (GTK_WINDOW (data->dialog), NULL);
 }