Remove not used zlib fragment.
Remove not used zlib fragment.

NewTree is called with the already deflated contents, there's no need to always fail creating a `zlib.NewReader` and waste memory with a new buffer we are just about to destroy.

fuchsia-mirror/third_party-github.com-src-d-go-git,go-git/go-git,src-d/go-git,ivanfoo/go-git,alcortesm/go-git,klaidliadon/go-git,alcortesm/go-git,ivanfoo/go-git,src-d/go-git,mcuadros/go-git,go-git/go-git,fuchsia-mirror/third_party-github.com-src-d-go-git,mcuadros/go-git