filemerge: add __bytes__ for absentfilectx
This will at _least_ aid some upcoming debugging.
Differential Revision: https://phab.mercurial-scm.org/D8592
# mercurial.revlogutils -- basic utilities for revlog
#
# 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.
from __future__ import absolute_import