Enable HDFS NameNode High Availability with HDP 2.0.6 plugin

Extend HDP 2.0.6 plugin to include the setup and configuration of the
HDFS NameNode High Availability after creating and configuring
the cluster.

Change-Id: I32116d42453bd3470b65bf863cf493f27301dab7
Implements: blueprint hdp-plugin-enable-hdfs-ha