Revert "SI-6601 Publicise derived value contstructor after pickler"

This reverts commit b07228aebe7aa620af45a681ef60d945ffc65665.

The remedy was far worse than the disease:

    % cat sandbox/test.scala
    class V private (val a: Any) extends AnyVal

    % RUNNER=scalac scala-hash b07228aebe sandbox/test.scala
    [info] b07228aebe => /Users/jason/usr/scala-v2.10.0-256-gb07228a

    % scala-hash b07228aebe
    [info] b07228aebe => /Users/jason/usr/scala-v2.10.0-256-gb07228a
    Welcome to Scala version 2.10.1-20130116-230935-b07228aebe (Java HotSpot(TM) 64-Bit Server VM, Java 1.6.0_27).
    Type in expressions to have them evaluated.
    Type :help for more information.

    scala> def foo(v: V) = v.a == v.a
    exception when typing v.a().==(v.a())/class scala.reflect.internal.Trees$Apply
    constructor V in class V cannot be accessed in object $iw in file <console>
    scala.reflect.internal.Types$TypeError: constructor V in class V cannot be accessed in object $iw

Review by @paulp