replica promotion: automatically add the local host to ipaservers
    
    If the user is authorized to modify members of the ipaservers host group,
    add the local host to ipaservers automatically.
    
    https://fedorahosted.org/freeipa/ticket/5401
    
    Reviewed-By: Martin Basti <mbasti@redhat.com>
    Reviewed-By: Simo Sorce <ssorce@redhat.com>