Fixing bug and removing useless log messages

src/GitHub.Api/Metrics/UsageModel.cs

@@ -17,7 +17,7 @@ namespace GitHub.Unity
 
     public class UsageModel
     {
-        private List<Usage> reports;
+        private List<Usage> reports = new List<Usage>();
 
         public IList<Usage> Reports
         {

src/GitHub.Api/Metrics/UsageTracker.cs

@@ -51,15 +51,6 @@ namespace GitHub.Unity
                 if (json != null)
                 {
                     result = SimpleJson.DeserializeObject<UsageStore>(json);
-                    if (result.Model == null)
-                    {
-                        Logger.Warning("Model is Null");
-                    }
-
-                    if (result.Model.Reports == null)
-                    {
-                        Logger.Warning("Reports is Null");
-                    }
                 }
                 else
                 {