Fix usings

Author: ErikEJ

src/Microsoft.Data.SqlClient/src/Microsoft/Data/SqlClient/TdsEnums.cs

@@ -3,11 +3,7 @@
 // See the LICENSE file in the project root for more information.
 
 using System;
-using System.Collections.Generic;
-using System.ComponentModel;
 using System.Data;
-using System.Diagnostics;
-using Microsoft.Data.Common;
 
 namespace Microsoft.Data.SqlClient
 {