[SPARK-LLAP-184] Use HDP 2.6.4.0 dependency (#185)
[SPARK-LLAP-184] Use HDP 2.6.4.0 dependency (#185)

## What changes were proposed in this pull request?

This PR updates the dependency to use the latest HDP (2.6.4.0).

## How was this patch tested?

Pass Travis CI only.
hortonworks-spark/spark-llap,hortonworks-spark/spark-llap,hortonworks-spark/spark-llap