The choice of '!' for a negative pathspec ends up not only not matching
what we do for revisions, it's also a horrible character for shell
expansion since it needs quoting.
So add '^' as an alternative alias for an excluding pathspec entry.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Junio C Hamano <gitster@pobox.com>