actionbar: Don't forall() widgets twice

When using forall(), only list the revealer, which lists the box
containing all the children. When using foreach(), bypass revealer and
box and list all children added to the box.

gtk/gtkactionbar.c

@@ -141,8 +141,7 @@ gtk_action_bar_forall (GtkContainer *container,
 
   if (include_internals)
     (* callback) (priv->revealer, callback_data);
- 
-  if (priv->box)
+  else if (priv->box)
     gtk_container_forall (GTK_CONTAINER (priv->box), callback, callback_data);
 }