address new Travis build warning (#2017)

* make explicit that which previously was fine

* suppress build warning

Octokit.Tests/Http/ApiConnectionTests.cs

@@ -388,6 +388,7 @@ namespace Octokit.Tests.Http
                 connection.Received(3).GetResponse<IReadOnlyList<object>>(queuedOperationUrl, Args.CancellationToken);
             }
 
+            [Fact(Skip = "Test triggers deadlock when run, needs to be investigated")]
             public async Task CanCancelQueuedOperation()
             {
                 var queuedOperationUrl = new Uri("anything", UriKind.Relative);

Octokit.Tests/Models/SearchIssuesRequestTests.cs

@@ -4,6 +4,8 @@ using System.Linq;
 using Octokit;
 using Octokit.Tests.Helpers;
 using Xunit;
+// hack because Travis on LInux is somehow upgraded to a version of .NET (Core?) that also has System.Range
+using Range = Octokit.Range;
 
 public class SearchIssuesRequestTests
 {