[gtk+/portal] Clear self->mode_data when freeing the data

[Matthias Clasen <matthiasc src gnome org>]

commit 3691ec0e7fe22d3a600f85416c4eb7fc7454398e
Author: Matthias Clasen <mclasen redhat com>
Date:   Wed Jul 6 20:55:10 2016 -0400

    Clear self->mode_data when freeing the data
    
    Pointed out by Cosimo.

 gtk/gtkfilechoosernativeportal.c |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)
---
diff --git a/gtk/gtkfilechoosernativeportal.c b/gtk/gtkfilechoosernativeportal.c
index ebff8fc..8838617 100644
--- a/gtk/gtkfilechoosernativeportal.c
+++ b/gtk/gtkfilechoosernativeportal.c
@@ -187,6 +187,7 @@ open_file_msg_cb (GObject *source_object,
       g_warning ("Can't open portal file chooser: %s", error->message);
       g_error_free (error);
       filechooser_portal_data_free (data);
+      self->mode_data = NULL;
       return;
     }
 
@@ -198,6 +199,7 @@ open_file_msg_cb (GObject *source_object,
       /* The dialog was hidden before we got the handle, close it now */
       send_close (data);
       filechooser_portal_data_free (data);
+      self->mode_data = NULL;
     }
   else
     {