[gtk+/portal] Trivial consistency fix

[Matthias Clasen <matthiasc src gnome org>]

commit 3b25a42637eed13e3220dbf4743b609150b27381
Author: Matthias Clasen <mclasen redhat com>
Date:   Wed Jul 6 20:18:04 2016 -0400

    Trivial consistency fix

 gtk/gtkfilechoosernativeportal.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/gtk/gtkfilechoosernativeportal.c b/gtk/gtkfilechoosernativeportal.c
index 66323c9..397bc6c 100644
--- a/gtk/gtkfilechoosernativeportal.c
+++ b/gtk/gtkfilechoosernativeportal.c
@@ -327,7 +327,7 @@ gtk_file_chooser_native_portal_show (GtkFileChooserNative *self)
   if (gtk_native_dialog_get_modal (GTK_NATIVE_DIALOG (self)))
     data->modal = TRUE;
 
-  if (data->modal && transient_for)
+  if (data->modal && transient_for != NULL)
     {
       data->grab_widget = gtk_invisible_new_for_screen (gtk_widget_get_screen (GTK_WIDGET (transient_for)));
       gtk_grab_add (GTK_WIDGET (data->grab_widget));