PPC/PPC64 disabled in Koji for dist-f13

[Josh Boyer]

Hi All,

As of today, ppc and ppc64 are no longer primary architectures in koji starting
with the dist-f13 tag.  This is in accordance with the FESCo approved demotion
of PowerPC starting with Fedora 13 development.

The dist-f12 and older tags continue to have them as primary.

Happy building.

josh