Make number of ElasticSearch shards and replicas configurable via usergrid props.
Merge branch 'two-dot-o' of https://git-wip-us.apache.org/repos/asf/incubator-usergrid into two-dot-o
Add new isHealthy() methods to EntityCollectionManager and EntityIndex, and add new HealthCheckFilter that calls them so we can fail fast when ES or C* not available.