Allow host re-enrollment using delegation
    
    A new option --force-join has been added to ipa-client-install.
    It forces the host enrollment even if the host entry exists.
    Old certificate is revoked, new certificate and ssh key pair
    generated. See the relevant design for the re-enrollment part:
    http://freeipa.org/page/V3/Forced_client_re-enrollment
    
    https://fedorahosted.org/freeipa/ticket/3482