Fix for TypeScript Typings

Without this fix users of TypeScript (at least 2.3.4) unable to import
the library using standard “import” syntax without either a) removing
the typings or b) using “require”.

index.d.ts

@@ -10,19 +10,15 @@
 declare namespace Express {
   interface Request extends ExpressValidator.RequestValidation {}
 }
-
-// External express-validator module.
-declare module "express-validator" {
   import express = require('express');
 
   /**
    * @param options see: https://github.com/ctavan/express-validator#middleware-options
    * @constructor
    */
-  function ExpressValidator(options?: ExpressValidator.Options.ExpressValidatorOptions): express.RequestHandler;
+  declare function ExpressValidator(options?: ExpressValidator.Options.ExpressValidatorOptions): express.RequestHandler;
 
   export = ExpressValidator;
-}
 
 // Internal Module.
 declare namespace ExpressValidator {