fix DeleteByQuery param white list (#748)

method delete_by_query can use the q parameter in the same way as the search api

Author: Rabotyahoff

src/Elasticsearch/Endpoints/DeleteByQuery.php

@@ -73,6 +73,7 @@ public function getParamWhitelist()
             'lenient',
             'preference',
             'query',
+            'q',
             'refresh',
             'request_cache',
             'requests_per_second',