merge-ort: shuffle the computation and cleanup of potential collisions
Run compute_collisions() for renames on both sides of history before
any calls to collect_renames(), and do not free the computed collisions
until after both calls to collect_renames(). This is just a code
reorganization at this point that doesn't make sense on its own, but
will permit us to use the computed collision info from both sides
within each call to collect_renames() in a subsequent commit.
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>