Merge branch 'cw/cherry-pick-allow-empty-message'

"git cherry-pick" by default stops when it sees a commit without any
log message.  The "--allow-empty-message" option can be used to
silently proceed.

* cw/cherry-pick-allow-empty-message:
  cherry-pick: add --allow-empty-message option

diff --cc Documentation/git-cherry-pick.txt
Simple merge