Fedora 18 changes the way how to work with services in spec files. It introduces new macros - %systemd_post, %systemd_preun and %systemd_postun; which replace scriptlets from Fedora 17 and older (see https://fedoraproject.org/wiki/Packaging:ScriptletSnippets#Systemd, https://bugzilla.redhat.com/show_bug.cgi?id=850016).
Jeff, Can you take a look at this? Thanks -steve
Changes made to rawhide and f18: http://pkgs.fedoraproject.org/cgit/heat.git/commit/?id=b709618fa62bc7d31134da770e8480667dfc6335