Indexer Elastic to ignore SSL issues

IndexerElastic (in 1.18) has no support for transporting over HTTPS, but 1.19 does. But 1.19 has no support for ignore SSL issues that are common with self-signed certificates.

This patch is for 1.18 only and was made without knowing SSL support was already there in master. Hence, the difference in config property naming, protocol (1.18/patch)  == scheme (1.19).