Merge branch 'bc/object-id'

Conversion from uchar[40] to struct object_id continues.

* bc/object-id:
pretty: switch hard-coded constants to the_hash_algo
sha1-file: convert constants to uses of the_hash_algo
log-tree: switch GIT_SHA1_HEXSZ to the_hash_algo->hexsz
diff: switch GIT_SHA1_HEXSZ to use the_hash_algo
builtin/merge-recursive: make hash independent
builtin/merge: switch to use the_hash_algo
builtin/fmt-merge-msg: make hash independent
builtin/update-index: simplify parsing of cacheinfo
builtin/update-index: convert to using the_hash_algo
refs/files-backend: use the_hash_algo for writing refs
sha1-name: use the_hash_algo when parsing object names
strbuf: allocate space with GIT_MAX_HEXSZ
commit: express tree entry constants in terms of the_hash_algo
hex: switch to using the_hash_algo
tree-walk: replace hard-coded constants with the_hash_algo
cache: update object ID functions for the_hash_algo

diff --cc builtin/fmt-merge-msg.c
Simple merge

diff --cc builtin/merge.c
Simple merge

diff --cc cache.h
Simple merge

diff --cc commit.c
Simple merge

diff --cc diff.c
Simple merge

diff --cc log-tree.c
Simple merge

diff --cc refs/files-backend.c
Simple merge

diff --cc sha1-name.c
Simple merge

diff --cc tree-walk.c
Simple merge