tests/test-gendoc-zh_CN.t

wireprotoserver: remove broken optimization for non-httplib client

There was an experimental non-httplib client in core for several
years. It was removed a week or so ago.

We kept the optimization for this client in the server code. I'm
not sure if that was intended or not. But it doesn't matter: the
code was wrong.

Because the code was accessing a WSGI environment dict, it needed to
access the HTTP_X_HGHTTP2 key to actually read the HTTP header. So
the code deleted by this commit wasn't actually doing anything
meaningful. Doh.

Differential Revision: https://phab.mercurial-scm.org/D2741

#require docutils gettext

  $ $TESTDIR/check-gendoc zh_CN
  checking for parse errors