function bindReqDeprecationNotice(req, key) {
  if (process.env.NODE_ENV === 'production' || req[key]) { return; }

  // Attach a getter
  Object.defineProperty(req, key, {
    value: function showDeprecationNotice() {
      var e = STRINGFILE.get('upgrade.req.' + key);
      throw new Error(e);
    }
  });
}
Bind deprecation notices for `req.*` properties from 0.8.x,
but only in development env, and only if the property
doesn't already exist (i.e. in case a user-defined
hook bound it on the `req` object.)

@param  {Request} req
@param  {String} key