fix multiple binding of same identifier in apply_coercion, broke core_extended
fix multiple binding of same identifier in apply_coercion, broke core_extended

git-svn-id: 152286350e621e20752d464a4cdb31881a3bf1ec@14215 f963ae5c-01c2-4b8c-9fe0-0dff7051ff02

msprotz/ocaml,gerdstolpmann/ocaml,eliberis/ocaml,eliberis/ocaml,gerdstolpmann/ocaml,yunxing/ocaml,yunxing/ocaml,msprotz/ocaml,gerdstolpmann/ocaml,yunxing/ocaml,eliberis/ocaml,msprotz/ocaml,eliberis/ocaml,yunxing/ocaml,gerdstolpmann/ocaml,msprotz/ocaml,eliberis/ocaml,yunxing/ocaml,msprotz/ocaml,gerdstolpmann/ocaml