[gtk+] Do not call popover_set_relative with NULL

[Matthias Clasen <matthiasc src gnome org>]

commit 2f379604d1f2211406b74aefd6553e2bd452ccc0
Author: Paolo Borelli <pborelli gnome org>
Date:   Sat Feb 15 11:30:53 2014 +0100

    Do not call popover_set_relative with NULL
    
    This gives a critical warning since that function expects a
    valid widget.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=724407

 gtk/gtkmenubutton.c |    1 -
 1 files changed, 0 insertions(+), 1 deletions(-)
---
diff --git a/gtk/gtkmenubutton.c b/gtk/gtkmenubutton.c
index c79cebe..3a81230 100644
--- a/gtk/gtkmenubutton.c
+++ b/gtk/gtkmenubutton.c
@@ -1097,7 +1097,6 @@ gtk_menu_button_set_popover (GtkMenuButton *menu_button,
       g_signal_handlers_disconnect_by_func (priv->popover,
                                             menu_deactivate_cb,
                                             menu_button);
-      gtk_popover_set_relative_to (GTK_POPOVER (priv->popover), NULL);
     }
 
   priv->popover = popover;