Don't rely on fixed Scala bug with inherited private fields

See https://issues.scala-lang.org/browse/SI-7475.

    class C { s1 =>
      private val q = ... // privates should not be inherited!

      new C { s2 =>
        // in Scala 2.11, this binds to s1.q, in 2.10 it buggily bound to `s2.q`
        q
      }
    }