Remove pkinit from ipa-replica-prepare
    
    The PKINIT feature is not available on domain level 0 so any
    options about pkinit are false.
    
    https://pagure.io/freeipa/issue/6759
    
    Reviewed-By: Martin Basti <mbasti@redhat.com>
    Reviewed-By: Jan Cholasta <jcholast@redhat.com>
    Reviewed-By: Alexander Bokovoy <abokovoy@redhat.com>