Cleanup usings

Author: AnthonyCarl

src/ServiceStack.Text.EnumMemberSerializer.UnitTests/EnumSerializerConfiguratorTests.cs

@@ -1,5 +1,4 @@
 using System;
-using System.Collections.Generic;
 using System.Reflection;
 using SomeOtherNamespace;
 using Xunit;

src/ServiceStack.Text.EnumMemberSerializer.UnitTests/EnumSerializerHelpersTests.cs

@@ -1,7 +1,4 @@
 using System;
-using System.Collections.Generic;
-using System.Linq;
-using System.Text;
 using Xunit;
 
 namespace ServiceStack.Text.EnumMemberSerializer.UnitTests