Merge branch 'jn/log-m-does-not-imply-p'

Earlier "git log -m" was changed to always produce patch output,
which would break existing scripts, which has been reverted.

* jn/log-m-does-not-imply-p:
  Revert 'diff-merges: let "-m" imply "-p"'

diff --cc Documentation/diff-options.txt
Simple merge