[gtk+/gtk-3-16] Plug another memory leak

[Matthias Clasen <matthiasc src gnome org>]

commit f30322bd98ada839d88a856b286077e1f71168a0
Author: Matthias Clasen <mclasen redhat com>
Date:   Tue Sep 15 10:54:29 2015 -0400

    Plug another memory leak

 demos/gtk-demo/listbox.c |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)
---
diff --git a/demos/gtk-demo/listbox.c b/demos/gtk-demo/listbox.c
index ee94d55..b309e35 100644
--- a/demos/gtk-demo/listbox.c
+++ b/demos/gtk-demo/listbox.c
@@ -164,6 +164,7 @@ gtk_message_row_update (GtkMessageRow *row)
   s = g_date_time_format (t, "%X - %e %b %Y");
   gtk_label_set_text (priv->detailed_time_label, s);
   g_free (s);
+  g_date_time_unref (t);
 
   gtk_widget_set_visible (GTK_WIDGET(priv->n_favorites_label),
                           priv->message->n_favorites != 0);