changelog: lazily parse user Same strategy as before. Revsets not accessing the user demonstrate a slight performance win: desc(bug) 0.887169 0.910400 0.895514 date(2015) 0.878797 0.870697 0.820987 extra(rebase_source) 0.865446 0.841644 0.823811 date(2015) or branch(default) 0.968276 0.945792 0.910981