* gtk/gtkfilechooserdialog.c
(file_chooser_widget_default_size_changed): Get the correct
initial size for the dialog. Also, don't bother with
gtk_window_set_default_size(). It's not really meaningful.
* gtk/gtkfilechooserdefault.c
(gtk_file_chooser_default_get_default_size): Get the correct
spacing for the preview_widget
(update_preview_widget_visibility): Clear widget field after we
destroy it.