Batteries.2.2.0 fails on OCaml 4.02.0 with an unbound Printf.CamlinternalPr

see ocaml-batteries-team/batteries-included#572
Merge pull request #2452 from avsm/batteries-ocaml-version

Batteries.2.2.0 fails on OCaml 4.02.0 with an unbound Printf.CamlinternalPR