Use default.conf as flag of IPA client being installed
    
    When installing / uninstalling IPA client, the checks that
    determine whether IPA client is installed now take the existence
    of /etc/ipa/default.conf into consideration.
    
    The client will not uninstall unless either something is backed
    up or /etc/ipa/default.conf file does exist.
    
    The client will not install if something is backed up or
    default.conf file does exist (unless it's installation on master).
    
    https://fedorahosted.org/freeipa/ticket/3331