tests/test-dirstate-backup.t

extensions: drop dead code trying to exclude deprecated disabled commands

Here 'ext' is a tuple, which means ext.__doc__ describes about the Python
tuple type. Fixing this would break 'hg help glog', which currently shows
some nice explanation, so this patch just removes the dead code.

  $ hg help glog
  'glog' is provided by the following extension:

      graphlog      command to view revision graphs from a shell (DEPRECATED)

  (use 'hg help extensions' for information on enabling extensions)

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