If there are non-mergeable changes leave the head contents in the
cache and update the working directory with the output from merge(1).
In the add/add and delete/modify conflict cases leave unmerged cache
entries in the index.
Signed-off-by: Fredrik Kuivinen <freku045@student.liu.se>
Signed-off-by: Junio C Hamano <junkio@cox.net>