Opened bug to track progress. Packaging guidelines have been updated. nginx matches one of the criteria for enabling _hardened_build: "Your package is long running. This means it's likely to be started and keep running until the machine is rebooted, not start on demand and quit on idle." http://fedoraproject.org/wiki/Packaging:Guidelines#PIE
nginx-1.0.15-2.fc17 has been submitted as an update for Fedora 17. https://admin.fedoraproject.org/updates/nginx-1.0.15-2.fc17
nginx-1.0.15-2.fc17 has been pushed to the Fedora 17 stable repository. If problems still persist, please make note of it in this bug report.