Let replicas install without DNS
    
    Let ipa-replica-prepare and ipa-replica-install work without
    proper DNS records as records in /etc/hosts are sufficient for
    DS replication.
    
      1) ipa-replica-prepare now just checks if the replica hostname
         is resolvable (DNS records are not required). It is now able
         to prepare a replica file even when the replica IP address is
         present in /etc/hosts only.
      2) ipa-replica-install is now able to proceed when the hostname
         is not resolvable. It uses an IP address passed in a new
         option --ip-address to create a record in /etc/hosts in the
         same way as ipa-server-install does.
    
    https://fedorahosted.org/freeipa/ticket/2139