hgweb: don't send a body or illegal headers during 304 response
Without this fix, mod_wsgi and spawning get in a wedged state after
sending a 304 response. Not sending a body fixed that problem. The
header change was discovered by using wsgiref.validate.validator to
check for other errors.
Basic install:
$ make # see install targets
$ make install # do a system-wide install
$ hg debuginstall # sanity-check setup
$ hg # see help
See http://mercurial.selenic.com/ for detailed installation
instructions, platform-specific notes, and Mercurial user information.