Update minimum required version of ocaml to 4.02.1

Summary:public
It seems that ocamlbuild from 4.02 does not pass -open Module to ocamlc when given an open(Module) tag.

Reviewed By: sblackshear

Differential Revision: D2947787

fb-gh-sync-id: 1544002
shipit-source-id: 1544002

configure.ac

@@ -152,7 +152,7 @@ fi
 AC_PROG_OCAML
 AC_ASSERT_PROG([ocamlc], [$OCAMLC])
 # check the version of OCaml
-AC_ASSERT_OCAML_MIN_VERSION([4.02.0])
+AC_ASSERT_OCAML_MIN_VERSION([4.02.1])
 AC_ASSERT_PROG([ocamlopt], [$OCAMLOPT])
 AC_ASSERT_PROG([ocamlbuild], [$OCAMLBUILD])
 AC_PROG_FINDLIB

opam

@@ -1,6 +1,6 @@
 opam-version: "1.2"
 name: "infer"
-version: "0.4.0"
+version: "0.7.0"
 maintainer: "opam-devel@lists.ocaml.org"
 authors: "Facebook"
 homepage: "https://github.com/facebook/infer"
@@ -13,6 +13,7 @@ build: [
 ]
 install: []
 remove: []
+ocaml-version: [ >= "4.02.1" ]
 depends: [
   "ocamlfind" {build}
   "sawja" {>="1.5.1"}