autopkgtest: add workaround for lxc+apparmor regression
PrivateNetwork=yes fails under lxc+apparmor, work around it by disabling it for now, to get autopkgtest back in shape. See: https://bugs.debian.org/1050256
PrivateNetwork=yes fails under lxc+apparmor, work around it by disabling it for now, to get autopkgtest back in shape. See: https://bugs.debian.org/1050256