Merge branch 'lt/diff-stat-show-0-lines'

We failed to mention a file without any content change but whose
permission bit was modified, or (worse yet) a new file without any
content in the "git diff --stat" output.

* lt/diff-stat-show-0-lines:
  Fix "git diff --stat" for interesting - but empty - file changes

diff --cc diff.c
Simple merge