tests/test-dirstate-backup.t

remotenames: introduce new template keywords for remotenames

This patch introduces three new template keywords 'remotenames',
'remotebookmarks', 'remotebranches' to show remotenames, remotebookmarks and
remotebranches associated to a changeset.

This is a part of moving hgremotenames extension to core. The remotenames
template keyword was present in the extension and the rest of the two are not
present in the hgremotenames extension and are introduced in this patch.

hgremotenames: https://bitbucket.org/seanfarley/hgremotenames

Differential Revision: https://phab.mercurial-scm.org/D1759

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