When we have a rename/rename(1to2) conflict, each of the renames can
collide with a file addition. Each of these rename/add conflicts suffered
from the same kinds of problems that normal rename/add suffered from.
Make the code use handle_file_conflicts() as well so that we get all the
same fixes and consistent behavior between the different conflict types.
Signed-off-by: Elijah Newren <newren@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>