Add logging imports to MutableSearchResponse

Author: drempapis

x-pack/plugin/async-search/src/main/java/org/elasticsearch/xpack/search/MutableSearchResponse.java

@@ -6,6 +6,7 @@
  */
 package org.elasticsearch.xpack.search;
 
+import org.apache.logging.log4j.Logger;
 import org.apache.lucene.search.TotalHits;
 import org.elasticsearch.ElasticsearchException;
 import org.elasticsearch.ExceptionsHelper;
@@ -14,6 +15,7 @@
 import org.elasticsearch.action.search.SearchResponseMerger;
 import org.elasticsearch.action.search.ShardSearchFailure;
 import org.elasticsearch.common.Strings;
+import org.elasticsearch.common.logging.Loggers;
 import org.elasticsearch.common.lucene.Lucene;
 import org.elasticsearch.common.util.concurrent.AtomicArray;
 import org.elasticsearch.common.util.concurrent.ThreadContext;