Running "cat-file --no-batch" will behave as if "--batch" was given,
since the option callback does not handle the "unset" flag (likewise for
"--no-batch-check").
In theory this might be used to cancel an earlier --batch, but it's not
immediately obvious how that would interact with --batch-check. Let's
just disallow the negated form of both options.
Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>