In parse_svn_date() prepend the correct UTC offset to the timestamp
returned.  This is the offset in effect at the commit time instead of
the offset in effect at calling time.
Signed-off-by: NUrs Thuermann <urs@isnogud.escape.de>
Reviewed-by: NEric Wong <e@80x24.org>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>