Merge branch 'rs/deflate-init-cleanup' into maint

Code simplification.

* rs/deflate-init-cleanup:
  zlib: initialize git_zstream in git_deflate_init{,_gzip,_raw}

diff --cc builtin/index-pack.c
Simple merge

diff --cc builtin/pack-objects.c
Simple merge

diff --cc bulk-checkin.c
Simple merge

diff --cc diff.c
Simple merge

diff --cc fast-import.c
Simple merge

diff --cc http-push.c
Simple merge

diff --cc remote-curl.c
Simple merge

diff --cc sha1_file.c
Simple merge