[gtk+] testheaderbar: fix a mmemonic

[Matthias Clasen <matthiasc src gnome org>]

commit 860197a7d2f6cc41212570f588bbbaf285387486
Author: Matthias Clasen <mclasen redhat com>
Date:   Fri Jun 28 16:08:15 2013 -0400

    testheaderbar: fix a mmemonic

 tests/testheaderbar.c |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)
---
diff --git a/tests/testheaderbar.c b/tests/testheaderbar.c
index ddfd826..88d2374 100644
--- a/tests/testheaderbar.c
+++ b/tests/testheaderbar.c
@@ -121,6 +121,7 @@ change_header (GtkButton *button, gpointer data)
       gtk_header_bar_set_title (GTK_HEADER_BAR (header), "Example header");
 
       widget = gtk_button_new_with_label ("_Close");
+      gtk_button_set_use_underline (GTK_BUTTON (widget), TRUE);
       gtk_style_context_add_class (gtk_widget_get_style_context (widget), "suggested-action");
       g_signal_connect (widget, "clicked", G_CALLBACK (gtk_main_quit), NULL);