testing: allow .debian.tar.xz files (e.g. Debian Jessie)
testing: allow .debian.tar.xz files (e.g. Debian Jessie)

LeMeteore/stdeb,sathieu/stdeb,astraw/stdeb,benthomasson/stdeb,pombredanne/stdeb,LeMeteore/stdeb,astraw/stdeb,benthomasson/stdeb,LeMeteore/stdeb,astraw/stdeb,benthomasson/stdeb,pombredanne/stdeb,pombredanne/stdeb,sathieu/stdeb,sathieu/stdeb