HSEARCH-2451 follow-up: removed an unused variable.

It shouldn't have been added in commit f82dd62

elasticsearch/src/main/java/org/hibernate/search/elasticsearch/impl/ElasticsearchHSQueryImpl.java

@@ -292,7 +292,6 @@ private void execute() {
 	private class IndexSearcher {
 
 		private final Map<String, Class<?>> entityTypesByName = new HashMap<>();
-		private final Map<String, Class<?>> documentBuilderIndexedEntityByName = new HashMap<>();
 		private final Set<String> indexNames = new HashSet<>();
 		private final String completeQueryAsString;