Fix backport

Author: russcam

src/Nest/Document/Multiple/MultiGet/Response/MultiGetHit.cs

@@ -1,6 +1,4 @@
-using System;
-using Elasticsearch.Net;
-using System;
+using Elasticsearch.Net;
 using Newtonsoft.Json;
 
 namespace Nest

src/Tests/Reproduce/GithubIssue2871.cs

@@ -49,7 +49,7 @@ public void IsValidFalseAndDeserializedErrorsWhenMultiGetDocHasErrors()
 			client.Bulk(b => b
 				.IndexMany(projects, (bi, p) => bi.Index(index1).Document(p))
 				.IndexMany(projects, (bi, p) => bi.Index(index2).Document(p))
-				.Refresh(Refresh.WaitFor)
+				.Refresh()
 			);
 
 			client.Alias(a => a