obsdiscovery: drop `obshash` discovery protocol (issue6136) The protocol has been superseeded by stablerange for a long time. It is untested and more and more buggy. Since this is deprecated experimental code in an experimental code, we drop it. We keep the underlying computation and debug command around for now. They might still be useful to looks at repositories

# Copyright 2019 Pierre-Yves David <pierre-yves.david@octobus.net>
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.

def hastopicext(repo):
    """True if the repo use the topic extension"""
    return getattr(repo, 'hastopicext', False)