SPARK-5607: Update to Kryo 2.24.0 to avoid including objenesis 1.2.

Our existing Kryo version actually embeds objenesis 1.2 classes in
its jar, causing dependency conflicts during tests. This updates us to
Kryo 2.24.0 (which was changed to not embed objenesis) to avoid this
behavior. See the JIRA for more detail.

Author: Patrick Wendell <patrick@databricks.com>

Closes #4383 from pwendell/SPARK-5607 and squashes the following commits:

c3b8d27 [Patrick Wendell] SPARK-5607: Update to Kryo 2.24.0 to avoid including objenesis 1.2.