Merge branch 'ps/the-index-is-no-more' into ps/undecided-is-not-necessarily-sha1

* ps/the-index-is-no-more:
  repository: drop `initialize_the_repository()`
  repository: drop `the_index` variable
  builtin/clone: stop using `the_index`
  repository: initialize index in `repo_init()`
  builtin: stop using `the_index`
  t/helper: stop using `the_index`

diff --cc builtin/add.c
Simple merge

diff --cc builtin/stash.c
Simple merge