tests/test-hghave.t

httppeer: improve protocol check

Pre-0.6c hgweb used text/plain for protocol responses. This meant
that a web server could serve a static file and confuse a client into
generating a nasty traceback.

Now we insist that text/plain protocol responses not include a
Content-Length, which older hgweb didn't generate but will typically
be produced for static files.

Testing that hghave does not crash when checking features

  $ "$TESTDIR/hghave" --test-features 2>/dev/null