Before objects are sent, the respective ref is locked. However,
without this patch, the lock is lifted before the last object for
that ref was sent. As a consequence, the lock data was accessed
after the lock structure was free()d.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>