[SPARK-4326] fix unidoc

There are two issues:

1. specifying guava 11.0.2 will cause hashInt not found in unidoc (any reason to force the version here?)
2. unidoc doesn't recognize static class defined in a base class

aarondav srowen vanzin

Author: Xiangrui Meng <meng@databricks.com>

Closes #3253 from mengxr/SPARK-4326 and squashes the following commits:

53967bf [Xiangrui Meng] fix unidoc