Less exciting Elasticsearch configuration

This slows down the speed Elasticsearch sends indicies from node to node
and turns off rack awareness.  Rack awareness was causing unbalanced load
across our cluster and the index copying was causing too much load.

DEPLOYMENT: This has all been applied directly to the cluster already.
This makes the changes stick across restarts.

Change-Id: I0b84282e70aef3e6d05b48f6a16dcf6ae1d833dd