[2.1.3-scala], Problem with fillAndValidate on Form

When I do a fold on my form after I have done a fillAndValidate the error function isn't called.

```scala
"The form mapping" should {

    import play.api.data._
    import play.api.data.Forms._
   
    "fold on error after fillAndValidate" in {
      case class Item(text: String)
      val itemForm = Form(mapping("text" -> nonEmptyText)(Item)(Item.unapply))
      val filled = itemForm.fillAndValidate(Item(""))

      val result = filled.fold(
        errors => false,
        success => true
      )
      result should beFalse
    }

    "find nested error on unbind" in {
      case class Item(text: String)
      case class Items(seq: Seq[Item])
      val itemForm = Form[Items](
        mapping(
          "seq" -> seq(
            mapping("text" -> nonEmptyText)(Item)(Item.unapply)
          )
        )(Items)(Items.unapply)
      )

      val result = itemForm.mapping.unbind(Items(Seq(Item(""))))
      result._2 must haveSize(1)
    }
  }
```