Monkey patch ES gem to handle v7 API total count

This is due to the breaking change introduced in ES7
https://www.elastic.co/guide/en/elasticsearch/reference/current/breaking-changes-7.0.html#hits-total-now-object-search-response
. This can be handled by the v7 client gem but since our main target is
ES6 for now we will just monkey patch the gem with this fix. When we
remove support for ES6 or use the ES7 gem and default to supporting ES7
then we can remove it.