Update Debian 6.0.8 to 6.0.9

One more time for the old-stable.

* Replace debian-6.0.8 templates with debian-6.0.9 ones with new image URLs and checksums
* Drop last digit from the preceed path, "debian-6.0" should be fine for all update releases
* Reorganize the templates a bit. Especially move variables ant `type` attributes to top for easier reading.