Fixed a couple more CA warnings.

Author: grokys

test/GitHub.InlineReviews.UnitTests/Services/PullRequestSessionTests.cs

@@ -18,7 +18,6 @@ namespace GitHub.InlineReviews.UnitTests.Services
     public class PullRequestSessionTests
     {
         const int PullRequestNumber = 5;
-        const string PullRequestNodeId = "pull_request_id";
         const string FilePath = "test.cs";
 
         public class TheHasPendingReviewProperty

test/TrackingCollectionTests/ListenerCollectionTests.cs

@@ -128,7 +128,7 @@ public void ResetingTrackingCollectionWorks()
         CollectionAssert.AreEqual(source, target);
     }
 
-    TrackingCollection<Thing> CreateSource()
+    static TrackingCollection<Thing> CreateSource()
     {
         var result = new TrackingCollection<Thing>(Observable.Empty<Thing>());
         result.Subscribe();