When DNS is already installed somewhere in topology we should not check for zone overlap because it would always say that we are overlapping our own domain. ipa-replica-install already does that but ipa-dns-install did not. https://fedorahosted.org/freeipa/ticket/5564 Reviewed-By: Petr Spacek <pspacek@redhat.com> Reviewed-By: Petr Vobornik <pvoborni@redhat.com>