hgweb_mod: partially undo 8afc25e7effc to fix py3
We now bytes-ify the entire request, so this is wrong.
Differential Revision: https://phab.mercurial-scm.org/D2308
To run the tests, do:
cd tests/
python run-tests.py
See https://mercurial-scm.org/wiki/WritingTests for
more information on writing tests.