configurehood: Only provide hood file from GW/KeyXchange via WWW

This will copy to hoodfilewww every 5 minutes!

Signed-off-by: Adrian Schmutzler <freifunk@adrianschmutzler.de>
Reviewed-by: Fabian Bläse <fabian@blaese.de>
Reviewed-by: Robert Langhammer <rlanghammer@web.de>
Reviewed-by: Tim Niemeyer <tim@tn-x.org>