Merge branch 'en/merge-ort-almost-wo-the-repository'

Merge branch 'en/merge-ort-almost-wo-the-repository'

Mark the marge-ort codebase to prevent more uses of the_repository
from getting added.

* en/merge-ort-almost-wo-the-repository:
  replay: prevent the_repository from coming back
  merge-ort: prevent the_repository from coming back
  merge-ort: replace the_hash_algo with opt->repo->hash_algo
  merge-ort: replace the_repository with opt->repo
  merge-ort: pass repository to write_tree()
  merge,diff: remove the_repository check before prefetching blobs