wireprotoserver: don't import symbol from hgweb.common
Importing hgweb.common requires importing hgweb.
hgweb/__init__.py contains a bit of code and does imports of large
parts of the hgweb.* module tree.
All we need is a constant defining the integer status code for
HTTP OK. So just redefine HTTP_OK in wireprotoserver.py and avoid
the excessive imports.
Differential Revision: https://phab.mercurial-scm.org/D1967
#require docutils gettext
$ $TESTDIR/check-gendoc da
checking for parse errors