fixed more tests.

NzbDrone.Core/Configuration/Config.cs

@@ -1,12 +1,13 @@
-using System.Linq;
 using NzbDrone.Core.Datastore;
+using ServiceStack.DataAnnotations;
 
 namespace NzbDrone.Core.Configuration
 {
     public class Config : ModelBase
     {
+        [Index(Unique = true)]
         public string Key { get; set; }
-        
+
         public string Value { get; set; }
     }
 }