Merge branch 'bc/object-id' into jch

Merge branch 'bc/object-id' into jch

Conversion from uchar[20] to struct object_id continues.

* bc/object-id:
  sha1_name: convert uses of 40 to GIT_SHA1_HEXSZ
  sha1_name: convert GET_SHA1* flags to GET_OID*
  sha1_name: convert get_sha1* to get_oid*
  Convert remaining callers of get_sha1 to get_oid.
  builtin/unpack-file: convert to struct object_id
  bisect: convert bisect_checkout to struct object_id
  builtin/update_ref: convert to struct object_id
  sequencer: convert to struct object_id
  remote: convert struct push_cas to struct object_id
  submodule: convert submodule config lookup to use object_id
  builtin/merge-tree: convert remaining caller of get_sha1 to object_id
  builtin/fsck: convert remaining caller of get_sha1 to object_id