[PATCH 20 of 21 WIP-PY3K] revset: use xrange from py3kcompat

[Matthew Turk]

# HG changeset patch
# User Matthew Turk <matthewturk at gmail.com>
# Date 1444684413 18000
#      Mon Oct 12 16:13:33 2015 -0500
# Node ID 59d00201f929e4296aada21845999bd9669a211e
# Parent  8f01ab5653b45779da0790fa0fb8ca3b6ca5e3d3
revset: use xrange from py3kcompat

diff -r 8f01ab5653b4 -r 59d00201f929 mercurial/revset.py
--- a/mercurial/revset.py	Mon Oct 12 16:13:10 2015 -0500
+++ b/mercurial/revset.py	Mon Oct 12 16:13:33 2015 -0500
@@ -24,6 +24,7 @@
     repoview,
     util,
 )
+from .py3kcompat import xrange
 
 def _revancestors(repo, revs, followfirst):
     """Like revlog.ancestors(), but supports followfirst."""