Setup and restore ntp configuration on the client side properly
When setting up the client-side NTP configuration, make sure that /etc/ntp/step-tickers
point to IPA NTP server as well.
When restoring the client during ipa-client-install --uninstall, make sure NTP configuration
is fully restored and NTP service is disabled if it was disabled before the installation.
https://fedorahosted.org/freeipa/ticket/1770