tests/test-phabricator.t

exchange: extract a function to sort obsolete markers

Follows up on changeset 01e8eefd9434, several other occurrences of
sorted() need to be fixed. The _sortedmarkers() handles sorting
obsmarkers with a None value as last element on Python 3.

#require vcr
  $ cat >> $HGRCPATH <<EOF
  > [extensions]
  > phabricator = 
  > EOF
  $ hg init repo
  $ cd repo
  $ cat >> .hg/hgrc <<EOF
  > [phabricator]
  > url = https://phab.mercurial-scm.org/
  > callsign = HG
  > 
  > [auth]
  > hgphab.schemes = https
  > hgphab.prefix = phab.mercurial-scm.org
  > # When working on the extension and making phabricator interaction
  > # changes, edit this to be a real phabricator token. When done, edit
  > # it back. The VCR transcripts will be auto-sanitised to replace your real
  > # token with this value.
  > hgphab.phabtoken = cli-hahayouwish
  > EOF
  $ VCR="$TESTDIR/phabricator"