casper uuid FIXME added

casper UUID seems randomly generated at initramfs creation, it is
added and unique to the image so the file (usually
casper-uuid-generic, depending on linux-image name) has to be
updated in the ISO root direcotry as .disk/casper-uuid-<kernel>.
for now just remove those casper uuid files from the ISO root and
hope for the best, this _should_ solve the issue with kernel
uprade in a dirty way
use dpkg-buildpackage instead of debuild which is part of dpkg-dev (build-essential) and more commonly installed