small fix in Lwt_js_event interface
small fix in Lwt_js_event interface

Ignore-this: 8297f93e948e639f1b1681a34fa7f835

darcs-hash:20120716174410-c4e55-03e8fa378915ca6f20623fc0444c84ba1f84a79e

alainfrisch/js_of_ocaml,alainfrisch/js_of_ocaml,OCamlPro-Henry/js_of_ocaml,alainfrisch/js_of_ocaml,alainfrisch/js_of_ocaml,OCamlPro-Henry/js_of_ocaml,OCamlPro-Henry/js_of_ocaml,alainfrisch/js_of_ocaml,OCamlPro-Henry/js_of_ocaml,OCamlPro-Henry/js_of_ocaml