hghave: fix up clang-libfuzzer regex to be bytes
Fixes this check on Python 3.
# skip-blame just a b prefix
Differential Revision: https://phab.mercurial-scm.org/D2607
<tr>
<td class="age">{date|rfc822date}</td>
<td class="author">{author|person}</td>
<td class="description">
<a href="{url|urlescape}rev/{node|short}{sessionvars%urlparameter}">{desc|strip|firstline|escape|nonempty}</a>
{alltags}
</td>
</tr>