Fix javadoc for module "elasticsearch"

Simplify non-arg constructor.

See #396.

Author: dr0i

metafacture-elasticsearch/src/main/java/org/metafacture/elasticsearch/JsonToElasticsearchBulk.java

@@ -46,14 +46,11 @@
 public class JsonToElasticsearchBulk extends DefaultObjectPipe<String, ObjectReceiver<String>> {
 
     private ObjectMapper mapper = new ObjectMapper();
-    private String[] idPath;
+    private String[] idPath = new String[] {};
     private String type;
     private String index;
 
     public JsonToElasticsearchBulk() {
-        this.idPath = new String[]{};
-        this.type = null;
-        this.index = null;
     }
 
     /**