For now, the download post-process logic uses mk_tar_gz, which repacks
a tarball compressed with gzip. So we can only accept as input a
tarball also compressed with gzip. To enforce that, this commit
changes post_process_unpack() to use tar xzf. This makes sure that if
a tarball compressed with something else than gzip gets used, it will
bail out and we will notice.
Support for other compression schemes can be added later on.
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
8ccff780f4