[gtk+] notebook: Fix boolean check

[Benjamin Otte <otte src gnome org>]

commit 9e2cdce58e081c3829008a256ecd8c3b5a7ce1de
Author: Benjamin Otte <otte redhat com>
Date:   Tue Mar 10 13:23:06 2015 +0100

    notebook: Fix boolean check
    
    Commit c352093bdeb2be5390607de13eaf7a21e93272ef swapped the condition
    when turning it into a return_if_fail().

 gtk/gtknotebook.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/gtk/gtknotebook.c b/gtk/gtknotebook.c
index d2d9354..8898260 100644
--- a/gtk/gtknotebook.c
+++ b/gtk/gtknotebook.c
@@ -8186,7 +8186,7 @@ gtk_notebook_query_tab_label_packing (GtkNotebook *notebook,
   g_return_if_fail (GTK_IS_WIDGET (child));
 
   list = CHECK_FIND_CHILD (notebook, child);
-  g_return_if_fail (!list);
+  g_return_if_fail (list != NULL);
 
   if (expand)
     *expand = GTK_NOTEBOOK_PAGE (list)->expand;