The re.sub() used to transform a tarball into a best guess folder name wasn't
right, as there isn't enough escaping and tar.xz was missing.
(From OE-Core rev: ac99135b009a1066486ed2afb2f298d0a5a3a854)
Signed-off-by: Ross Burton <ross.burton@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>