[gtk] stack: Fix a corner-case

[Matthias Clasen <matthiasc src gnome org>]

commit 17509226316b0658a0c789af43c3f28de0fe0435
Author: Matthias Clasen <mclasen redhat com>
Date:   Wed Feb 13 09:00:00 2019 -0500

    stack: Fix a corner-case
    
    When the stack goes empty, we were failing to reset
    the visible_child member to NULL, causing problems later
    on, since we don't have a ref for it.

 gtk/gtkstack.c | 3 ---
 1 file changed, 3 deletions(-)
---
diff --git a/gtk/gtkstack.c b/gtk/gtkstack.c
index c1c843a45a..ba80e9faf3 100644
--- a/gtk/gtkstack.c
+++ b/gtk/gtkstack.c
@@ -1140,9 +1140,6 @@ set_visible_child (GtkStack               *stack,
   if (child_info == priv->visible_child)
     return;
 
-  if (child_info == NULL)
-    return;
-
   if (priv->pages)
     {
       guint position;