tests/test-backwards-remove.t

lfs: add the '{oid}' template keyword to '{lfs_files}'

The 'sha256:' prefix is skipped because this seems like the most convenient way
to consume it.  Maybe we should also add a '{oid_type}' keyword?  Then again,
that can be added in the future if a different algorithm is supported.

  $ hg init
  $ echo This is file a1 > a
  $ hg add a
  $ hg commit -m "commit #0"
  $ ls
  a
  $ echo This is file b1 > b
  $ hg add b
  $ hg commit -m "commit #1"
  $ hg co 0
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved

B should disappear

  $ ls
  a