Add a regression test for the git log -M --follow $diff_option bug
introduced in v1.7.2-rc0~103^2~2, $diff_option being diff related
options like -p, --stat, --name-only etc.
Signed-off-by: NÆvar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>