Fixed an issue where a none-paused empty queue would throw.

NzbDrone.Core.Test/Files/QueueEmpty.txt

@@ -31,7 +31,6 @@
     "color_scheme":"",
     "darwin":false,
     "nt":true,
-    "status":"Paused",
     "last_warning":"",
     "have_warnings":"0",
     "cache_art":"0",

NzbDrone.Core/Providers/SabProvider.cs

@@ -203,7 +203,7 @@ namespace NzbDrone.Core.Providers
         {
             var result = JsonConvert.DeserializeObject<SabJsonError>(response);
 
-            if (result.Status.Equals("false", StringComparison.InvariantCultureIgnoreCase))
+            if (result.Status != null && result.Status.Equals("false", StringComparison.InvariantCultureIgnoreCase))
                 throw new ApplicationException(result.Error);
         }
     }