These were added by 8bf4bec (add "ok=sigpipe" to
test_must_fail and use it to fix flaky tests, 2015-11-27)
because we would racily die via SIGPIPE when the pack was
rejected by the other side.
But since we have recently de-flaked send-pack, we should be
able to tighten up these tests (including re-adding the
expected output checks).
Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>