hgweb: fix unbundle. After the WSGI changes, even if a push over HTTP succeeds, apache complains about "Premature end of script headers: hgwebdir.cgi" and returns a "HTTP Error 500: Internal Server Error", making the local hg abort. The change to either of the files touched by this patch is enough to fix this, but I think changing both is a more robust solution.

# repo.py - repository base classes for mercurial
#
# Copyright 2005 Matt Mackall <mpm@selenic.com>
#
# This software may be used and distributed according to the terms
# of the GNU General Public License, incorporated herein by reference.

class RepoError(Exception): pass