Delete Es7DAO.java (#6397)

oap-server/server-storage-plugin/storage-elasticsearch7-plugin/src/main/java/org/apache/skywalking/oap/server/storage/plugin/elasticsearch7/Es7DAO.java

-/*
- * Licensed to the Apache Software Foundation (ASF) under one or more
- * contributor license agreements.  See the NOTICE file distributed with
- * this work for additional information regarding copyright ownership.
- * The ASF licenses this file to You under the Apache License, Version 2.0
- * (the "License"); you may not use this file except in compliance with
- * the License.  You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- *
- */
-
-package org.apache.skywalking.oap.server.storage.plugin.elasticsearch7;
-
-import org.apache.skywalking.oap.server.core.storage.AbstractDAO;
-import org.apache.skywalking.oap.server.storage.plugin.elasticsearch7.client.ElasticSearch7Client;
-
-public class Es7DAO extends AbstractDAO<ElasticSearch7Client> {
-    public Es7DAO(final ElasticSearch7Client client) {
-        super(client);
-    }
-}