Two patches;
0001) Do not include boot.iso on any disc, per https://www.redhat.com/archives/fedora-devel-list/2009-January/msg02070.html
0002) the more cosmetic patch, I just so happened to see this; extraargs had two append() calls while "-o" and isofile were meant to be together. The patch makes this one extend call so that no accidents happen when someone inserts a line in between.
Kind regards,
Jeroen van Meeuwen -kanarip