This test just checks that old clients can clone and fetch
from a newer git-daemon. The opposite should also be true,
but it's hard to test ancient versions of git-daemon because
they lack basic options like "--listen".
Note that we have to make a slight tweak to the
lib-git-daemon helper from the regular tests, so that it
starts the daemon with our correct git.a version.
Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>