git.el: Added support for Signed-off-by.
git.el: Added support for Signed-off-by.

If `git-append-signed-off-by' is non-nil, automatically append a
sign-off line to the log message when editing it.

Signed-off-by: Alexandre Julliard <a3c1c71ac0d85b781251f68481a696b8e4d0781d@winehq.org>
Signed-off-by: Junio C Hamano <dc50d1021234060e53ec42a77d526afa2fe07479@cox.net>

destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git