[gtk+/gtk-3-22] applicationwindw: Don't leak show-help-overlay action

[Daniel Boles <dboles src gnome org>]

commit b3f4da0439761b32369315afbcad57d0a9bbbae0
Author: Timm Bäder <mail baedert org>
Date:   Fri Oct 6 16:30:31 2017 +0200

    applicationwindw: Don't leak show-help-overlay action

 gtk/gtkapplicationwindow.c |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)
---
diff --git a/gtk/gtkapplicationwindow.c b/gtk/gtkapplicationwindow.c
index 20f2abd..370d0ca 100644
--- a/gtk/gtkapplicationwindow.c
+++ b/gtk/gtkapplicationwindow.c
@@ -1024,6 +1024,7 @@ gtk_application_window_set_help_overlay (GtkApplicationWindow *window,
       g_signal_connect (action, "activate", G_CALLBACK (show_help_overlay), window);
 
       g_action_map_add_action (G_ACTION_MAP (window->priv->actions), G_ACTION (action));
+      g_object_unref (G_OBJECT (action));
     }
 }