merge-ort: add implementation of type-changed rename handling
Implement cases where renames are involved in type changes (i.e. the
side of history that didn't rename the file changed its type from a
regular file to a symlink or submodule). There was some code to handle
this in merge-recursive but only in the special case when the renamed
file had no content changes. The code here works differently -- it
knows process_entry() can handle mode conflicts, so it does a few
minimal tweaks to ensure process_entry() can just finish the job as
needed.
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>