Directly policy - too much retries

[Matzz]

Direct policy retries one more time than specified. There is test which shows that:

    it ("should deal with future failures") {
      implicit val success = Success.always
      val policy = retry.Directly(3)
      val counter = new AtomicInteger()
      val future = policy { () =>
        counter.incrementAndGet()
        Future.failed(new RuntimeException("always failing"))
      }
      Await.ready(future, Duration.Inf)
      assert(counter.get() === 4)
    }

In documentation there is

// retry 4 times
val future = retry.Directly(4) {
  attempt
}

which is inconsistent with test

[softprops]

I can probably document this better. in the test I'm expressing the want to retry something up to 3 times if the initial try fails, according to what success is defined as. the first attempt + 3 retries == 4 . I'll try to update the docs to make that clearer.