D1201: dirstate: clean up when restoring identical backups

[martinvonz (Martin von Zweigbergk)]

martinvonz added a comment.


  In https://phab.mercurial-scm.org/D1201#20829, @durham wrote:
  
  > lgtm.  Is this a recent regression?  Seems like this would be polluting lots of peoples repositories.
  
  
  I never noticed, but now that you ask, here's in my hg repo:
  
  $ ls -1 .hg/dirstate.backup.import.*
  .hg/dirstate.backup.import.139672779498704
  .hg/dirstate.backup.import.139940118873296
  .hg/dirstate.backup.import.140117795275984
  .hg/dirstate.backup.import.140181671269584
  .hg/dirstate.backup.import.140261652248144
  .hg/dirstate.backup.import.140345443734736
  .hg/dirstate.backup.import.140542706046160
  .hg/dirstate.backup.import.140585297004112

REPOSITORY
  rHG Mercurial

REVISION DETAIL
  https://phab.mercurial-scm.org/D1201

To: mbthomas, #hg-reviewers, krbullock, durham
Cc: martinvonz, krbullock, durham, mercurial-devel