[gtk+] Fix precondition in gtk_popover_get_default_widget

[Matthias Clasen <matthiasc src gnome org>]

commit 1f51c506c3ce0930c0c4fc616a176c5f96b34781
Author: Matthias Clasen <mclasen redhat com>
Date:   Mon May 4 09:27:02 2015 -0400

    Fix precondition in gtk_popover_get_default_widget
    
    We need to return a value here.

 gtk/gtkpopover.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/gtk/gtkpopover.c b/gtk/gtkpopover.c
index 5c9103e..827c593 100644
--- a/gtk/gtkpopover.c
+++ b/gtk/gtkpopover.c
@@ -2423,7 +2423,7 @@ gtk_popover_get_default_widget (GtkPopover *popover)
 {
   GtkPopoverPrivate *priv = popover->priv;
 
-  g_return_if_fail (GTK_IS_POPOVER (popover));
+  g_return_val_if_fail (GTK_IS_POPOVER (popover), NULL);
 
   return priv->default_widget;
 }