stripspace: make sure not to leave an incomplete line.

stripspace: make sure not to leave an incomplete line.

When dealing with a commit log message for human consumption, it
never makes sense to keep a log that ends with an incomplete
line, so make it a part of the clean-up process done by
git-stripspace.

Acked-by: Linus Torvalds <torvalds@osdl.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>