We should be letting the user's umask take care of
restricting permissions. Even though this is a temporary
file and probably nobody would notice, this brings us in
line with other temporary file creations in git (e.g.,
choosing "e"dit from git-add--interactive).
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>