Support body in DELETE requests

[szajbus]

In clear scroll API, Elasticsearch requires scroll_id to be passed in request body:

DELETE /_search/scroll
{
    "scroll_id" : "DXF1ZXJ5QW5kRmV0Y2gBAAAAAAAAAD4WYm9laVYtZndUQlNsdDcwakFMNjU1QQ=="
}

https://www.elastic.co/guide/en/elasticsearch/reference/6.4/search-request-scroll.html

[adjivas]

Hello, Thank's a lot for your work :) this PR will be merged?

[szajbus]

I think this is not really needed anymore, you can simply do

Elasticsearch.delete(cluster, "/_search/scroll/#{scroll_id}")