Enforce host existence only where needed in ipa-replica-manage
    
    In ipa-replica-manage commands, we enforce that hostnames we work
    with are resolvable. However, this caused errors while deleting
    or disconnecting a ipa / winsync replica, if that replica was down
    and authoritative server for itself.
    
    Also adds an --no-lookup flag to disable host existence checks.
    
    https://fedorahosted.org/freeipa/ticket/3524