[gtk] widget: Remove an unused signal

[Matthias Clasen <matthiasc src gnome org>]

commit 448a4023539823c8da0d950e37c6a4de6faff0cb
Author: Matthias Clasen <mclasen redhat com>
Date:   Sun Jan 5 09:19:29 2020 -0500

    widget: Remove an unused signal
    
    HIERARCHY_CHANGED is no longer used.

 gtk/gtkwidget.c | 1 -
 1 file changed, 1 deletion(-)
---
diff --git a/gtk/gtkwidget.c b/gtk/gtkwidget.c
index 3d40eee3d1..8119b06fd4 100644
--- a/gtk/gtkwidget.c
+++ b/gtk/gtkwidget.c
@@ -511,7 +511,6 @@ enum {
   UNREALIZE,
   SIZE_ALLOCATE,
   STATE_FLAGS_CHANGED,
-  HIERARCHY_CHANGED,
   DIRECTION_CHANGED,
   GRAB_NOTIFY,
   CHILD_NOTIFY,