tests/test-dirstate-backup.t

templatekw: make getrenamed() return only filename, not nodeid

No callers cared about the nodeid and I want to make getrenamed() not
look up the node (although it's currently free, I hope to store copy
info in changesets and not include the nodeid).

Differential Revision: https://phab.mercurial-scm.org/D3666

Set up

  $ hg init repo
  $ cd repo

Try to import an empty patch

  $ hg import --no-commit - <<EOF
  > EOF
  applying patch from stdin
  abort: stdin: no diffs found
  [255]

No dirstate backups are left behind

  $ ls .hg/dirstate* | sort
  .hg/dirstate