The unpack-objects command should not generally produce any
output on stdout. However, if it's given extra input after
the packfile, it will spew the remainder to stdout. When
called by receive-pack, this means we will break protocol,
since our stdout is connected to the remote send-pack.
Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>