Merge branch 'mh/war-on-extra-refs'

* mh/war-on-extra-refs:
  refs: remove the extra_refs API
  clone: do not add alternate references to extra_refs
  everything_local(): mark alternate refs as complete
  fetch-pack.c: inline insert_alternate_refs()
  fetch-pack.c: rename some parameters from "path" to "refname"
  clone.c: move more code into the "if (refs)" conditional
  t5700: document a failure of alternates to affect fetch