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).
Created attachment 631584 [details] Patch replaces scriptlets with new systemd macros
libvirt-qmf if retired/deprecated in F19+, so I don't think anyone is going to put in the effort to fix this for F18. Closing as WONTFIX