use DM credentials to retrieve service keytab only in DLO
    
    In DL0 directory manager password is bundled in the supplied replica file and
    the replica installer can use it to authenticate against master when
    retrieving service keytabs.
    
    In DL1, however, DM credentials are generated randomly and used during local
    DS instance creation. The proper DM password is imported by custodia much
    later to the process. We must not allow the installer to contact the remote
    master using this random password since it would fail.
    
    https://fedorahosted.org/freeipa/ticket/6405
    
    Reviewed-By: Stanislav Laznicka <slaznick@redhat.com>