disable ipa-replica-prepare in non-zero IPA domain level
    
    the original replica installation path (ipa-replica-prepare +
    ipa-replica-install) remains valid only when IPA domain level is zero. When
    this is not the case, ipa-replica-prepare will print out an error message which
    instructs the user to use the new replica promotion machinery to setup
    replicas.
    
    https://fedorahosted.org/freeipa/ticket/5175
    
    Reviewed-By: Martin Basti <mbasti@redhat.com>