Logically, -m, -c, --cc specify 3 different formats for representing
merge commits, yet -m doesn't in fact override -c or --cc, that makes
no sense.
Add 2 expected to fail tests that demonstrate the problem.
Signed-off-by: Sergey Organov <sorganov@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
