[ocamlformat] Exclude deadcode/dune.in from list of ocaml dune files
[ocamlformat] Exclude deadcode/dune.in from list of ocaml dune files

Summary:
infer/src/deadcode/dune.in is not an OCaml-syntax dune file, so
exclude it from the list computed for use by the auto-formatter.

Reviewed By: jvillard

Differential Revision: D21583047

fbshipit-source-id: 13a99a89b

jvillard/infer,facebook/infer,facebook/infer,facebook/infer,jvillard/infer,facebook/infer,jvillard/infer,jvillard/infer,facebook/infer,jvillard/infer,jvillard/infer,facebook/infer,facebook/infer,jvillard/infer