The named service, which was enabled prior to the upgrade, was disabled after upgrading from F16 to F17 as per https://fedoraproject.org/wiki/Upgrading_Fedora_using_yum. I suspect this is because it was converted from initscripts to systemd. The instructions at the URL referenced above say to check which services are enabled before upgrading to F16 and re-enable them afterward, but it doesn't say the same thing about upgrading to F17. If there are services being converted from initscripts to systemd in F17, then either (a) they need to automatically save and restore their status during the upgrade, or (b) the instructions at the URL mentioned above need to explain how to preserve the status of those services when upgrading.
Per http://lists.fedoraproject.org/pipermail/devel/2012-April/165917.html this kind of changes isn't documented, closing. If you disagree and think that this should be documented somewhere, please reopen this bug.