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).
Fixed in GIT: http://git.fedorahosted.org/cgit/firewalld.git/commit/?id=e1cbb62ac0321b2997ae6f1cbe58431226451f89 Also part of 0.2.8 release.