We have something much better now: --rebase-merges (which is a
complete re-design --preserve-merges, with a lot of issues fixed such as
the inability to reorder commits with --preserve-merges).
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>