Merge branch 'dd/no-gpg-sign'

"git rebase" learned the "--no-gpg-sign" option to countermand
commit.gpgSign the user may have.

* dd/no-gpg-sign:
  Documentation: document merge option --no-gpg-sign
  Documentation: merge commit-tree --[no-]gpg-sign
  Documentation: reword commit --no-gpg-sign
  Documentation: document am --no-gpg-sign
  cherry-pick/revert: honour --no-gpg-sign in all case
  rebase.c: honour --no-gpg-sign

diff --cc Documentation/git-rebase.txt
Simple merge

diff --cc builtin/rebase.c
Simple merge

diff --cc sequencer.c
Simple merge