Merge branch 'bc/rev-list-without-commit-line'

"git rev-list" learns to omit the "commit <object-name>" header
lines from the output with the `--no-commit-header` option.

* bc/rev-list-without-commit-line:
  rev-list: add option for --pretty=format without header

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

diff --cc revision.h
Simple merge