local.conf: disable tar.gz images, tar.xz should be enough
local.conf: disable tar.gz images, tar.xz should be enough

Other image formats specified in MACHINE.conf files will still get
built, only 'tar.gz' has been disabled.

Signed-off-by: Koen Kooi <42e3d96910f922bdd7dd1805fe3f8aff634f391d@dominion.thruhere.net>

Angstrom-distribution/setup-scripts,wwright2/angstrom-setup.methode,Ambertec/setup-scripts