[gnome-panel/gtk3] Use gtk_widget_unset_state_flags() instead of sealed GtkButton fields

[Milan Bouchet-Valat <milanbv src gnome org>]

commit 60ffb648c3b0e2dfc188cb79431e98ed4859c373
Author: David Ronis <david ronis mcgill ca>
Date:   Wed Dec 29 22:33:30 2010 +0100

    Use gtk_widget_unset_state_flags() instead of sealed GtkButton fields
    
    Previous commit missed that occurrence.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=627455

 gnome-panel/panel-menu-button.c |    4 +++-
 1 files changed, 3 insertions(+), 1 deletions(-)
---
diff --git a/gnome-panel/panel-menu-button.c b/gnome-panel/panel-menu-button.c
index b02448e..7c29ae6 100644
--- a/gnome-panel/panel-menu-button.c
+++ b/gnome-panel/panel-menu-button.c
@@ -349,7 +349,9 @@ panel_menu_button_menu_deactivated (PanelMenuButton *button)
 {
 	panel_toplevel_pop_autohide_disabler (button->priv->toplevel);
 
-	GTK_BUTTON (button)->GSEAL(in_button) = FALSE;
+	gtk_widget_unset_state_flags (GTK_WIDGET (button),
+				      GTK_STATE_FLAG_PRELIGHT);
+
 	button_widget_set_ignore_leave (BUTTON_WIDGET (button), FALSE);
 }