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