Code review comment for lp:~mbp/bzr/415508-content-filtering

The code and tests look good to me. The docstring and code in _path_content_summary() aren't obviously in sync but I don't have good ideas for improving either. Perhaps dirstate_sha1 should be called dirstate_fingerprint instead?

The NEWS items needs a trivial tweak: 'of file' -> 'of a file'.