This updates the Elasticsearch chart to include a specific start
script for the Elasticsearch data nodes that includes a trap on
signals that removes a data node from allocation eligible nodes
before shutting down. This results in all shards being moved from
a node on shut down to alleviate issues with planned down nodes,
such as during upgrade scenarios
Change-Id: I22f4957f90e4113831a8ddf48691cb14f811c1e5