The Wi-Fi and mobile broadband row's visibility depends on related
device status. But calling gtk_widget_show_all on the whole list box
makes them visible even related device is not avialbe. Fix that by
setting no-show-all of these two widgets as TRUE.
https://gitlab.gnome.org/GNOME/gnome-control-center/issues/189
Signed-off-by: Chen Wei <chenwei@xfusion.com>