Remove keywords for s6, it's in the stable tree now
Remove keywords for s6, it's in the stable tree now

jonasjonas/gentoo-bb,gdm/gentoo-bb,edannenberg/gentoo-bb,jonasjonas/gentoo-bb,guruvan/gentoo-bb,berney/gentoo-bb,edannenberg/gentoo-bb,guruvan/gentoo-bb,gdm/gentoo-bb,edannenberg/kubler,berney/gentoo-bb