a bit of cleanup

Octokit.Tests.Conventions/PaginationTests.cs

@@ -8,7 +8,7 @@ namespace Octokit.Tests.Conventions
 {
     public class PaginationTests
     {
-        [Theory(Skip = "Disable this to run it and find all the places where things break")]
+        [Theory(Skip = "Enable this to run it and find all the places where things break")]
         [MemberData("GetClientInterfaces")]
         public void CheckObservableClients(Type clientInterface)
         {

Octokit.Tests/Clients/ReleasesClientTests.cs

@@ -20,7 +20,7 @@ namespace Octokit.Tests.Clients
 
                 client.Received().GetAll<Release>(Arg.Is<Uri>(u => u.ToString() == "repos/fake/repo/releases"),
                     null,
-                    AcceptHeaders.StableVersion,
+                    "application/vnd.github.v3",
                     Args.ApiOptions);
             }
 

Octokit/Http/ApiConnection.cs

@@ -1,8 +1,6 @@
 using System;
 using System.Collections.Generic;
 using System.Collections.ObjectModel;
-using System.Globalization;
-using System.Linq;
 using System.Net;
 using System.Threading;
 using System.Threading.Tasks;