GeezerVison

…x numbers in tarfile

When a pax extended header carried a malformed GNU sparse number, tarfile
parsed it with a bare int() and let the resulting ValueError escape to the
caller from _proc_gnusparse_01, _proc_gnusparse_10, and the GNU.sparse.size
and GNU.sparse.realsize branches of _apply_pax_info, unlike the GNU sparse
0.0 handler which already reports such corruption as InvalidHeaderError. Wrap
those conversions so a bad number raises tarfile.InvalidHeaderError, which the
reader treats as end of archive, giving the whole GNU sparse family
consistent behavior on a corrupt header.