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.
To run the tests, do:
cd tests/
python run-tests.py
See https://mercurial-scm.org/wiki/WritingTests for
more information on writing tests.