Versions of Maven older than 3.3.0 apparently have [a bug in how they handle transitive dependencies](https://github.com/apache/spark/pull/6492#issuecomment-111001101).

I confirmed that upgrading to Maven 3.3.3 resolves at least the particular manifestation of this bug that I ran into.

Author: Nicholas Chammas <nicholas.chammas@gmail.com>

Closes #6770 from nchammas/maven-333 and squashes the following commits:

6bed2d9 [Nicholas Chammas] upgrade to Maven 3.3.3