[merlin] disable warning 60 (unused module declaration)
[merlin] disable warning 60 (unused module declaration)

Summary:
Every module declared but not used in the same source file is warned about
currently. Disable the noisy warning.

For instance, before this diff (and after "M-x merlin-restar-process"):

1. open AbstractInterpreter.ml
2. merlin shows a warning for `module Make` inside emacs

Reviewed By: jberdine

Differential Revision: D5621383

fbshipit-source-id: c175e5d

jvillard/infer,ropas/infer,jvillard/infer,blzq/infer,blzq/infer,jvillard/infer,ropas/infer,facebook/infer,ropas/infer,facebook/infer,blzq/infer,jvillard/infer,facebook/infer,facebook/infer,jvillard/infer,facebook/infer,blzq/infer,ropas/infer,ropas/infer,jvillard/infer,facebook/infer,blzq/infer,facebook/infer,jvillard/infer,ropas/infer,blzq/infer