Array.Empty not available for .NET 4.5

Author: Mpdreamz

src/Tests/Framework/ManagedElasticsearch/Clusters/XPackCluster.cs

@@ -11,9 +11,9 @@ public class XPackCluster : ClusterBase
 	{
 		protected string[] XPackSettings => TestClient.VersionUnderTestSatisfiedBy(">=5.5.0")
 			? new[] {"xpack.security.authc.token.enabled=true"}
-			: Array.Empty<string>();
+			: new string[] {} ;
 
-        protected override string[] AdditionalServerSettings => base.AdditionalServerSettings.Concat(this.XPackSettings).ToArray();
+		protected override string[] AdditionalServerSettings => base.AdditionalServerSettings.Concat(this.XPackSettings).ToArray();
 
 		public override ConnectionSettings ClusterConnectionSettings(ConnectionSettings s) =>
 			s.BasicAuthentication("es_admin", "es_admin");