Log contents on api errors during tests.

(cherry picked from commit f2e1b4e43549695afacee5c87cca368e8fa30905)

Closes #295

src/NzbDrone.Integration.Test/Client/ClientBase.cs

@@ -55,7 +55,7 @@ namespace NzbDrone.Integration.Test.Client
 
             response.ErrorMessage.Should().BeNullOrWhiteSpace();
 
-            response.StatusCode.Should().Be(statusCode);
+            response.StatusCode.Should().Be(statusCode, response.Content ?? string.Empty);
 
             return response.Content;
         }