subrepo: use code from 71ea5b2b9517 only if Python needs it (issue2795)
With Python >= 2.6 the original code already works correct, therefore the
fix for issue2556 on Python <= 2.5 broke relative subrepositories with
newer versions of Python.
$ "$TESTDIR/hghave" inotify || exit 80
$ hg init
$ echo "[extensions]" > .hg/hgrc
$ echo "inotify=" >> .hg/hgrc
$ hg inserve -d --pid-file .hg/inotify.pid
$ echo a > a
$ hg ci -Aqm0
$ hg co -q null
$ hg co -q
$ hg st
$ cat a
a
$ kill `cat .hg/inotify.pid`