Added sanity checks for missing image repos.
Added sanity checks for missing image repos.

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