Specialize Scala 2.11 feature for 2.11 and 2.12 build

The Scala 2.11 feature for the 2.11 build has a reference to the bundled
Scala 2.10 jar. We don't want this reference for the Scala 2.12 build.

This will be removed when the need of the bundled Scala 2.10 jar is fixed.