Fixed issue trying getting parent of drive

src/NzbDrone.Core.Test/Download/DownloadClientTests/SabnzbdTests/SabnzbdFixture.cs

@@ -268,5 +268,18 @@ namespace NzbDrone.Core.Test.Download.DownloadClientTests.SabnzbdTests
 
             result.OutputPath.Should().Be(@"C:\sorted\Droned.S01E01.Pilot.1080p.WEB-DL-DRONE".AsOsAgnostic());
         }
+
+        [Test]
+        public void should_not_blow_up_if_storage_is_drive_root()
+        {
+            _completed.Items.First().Storage = @"C:\".AsOsAgnostic();
+
+            WithQueue(null);
+            WithHistory(_completed);
+
+            var result = Subject.GetItems().Single();
+
+            result.OutputPath.Should().Be(@"C:\".AsOsAgnostic());
+        }
     }
 }

src/NzbDrone.Core/Download/Clients/Sabnzbd/Sabnzbd.cs

@@ -162,7 +162,7 @@ namespace NzbDrone.Core.Download.Clients.Sabnzbd
                 if (!sabHistoryItem.Storage.IsNullOrWhiteSpace())
                 {
                     var parent = Directory.GetParent(sabHistoryItem.Storage);
-                    if (parent.Name == sabHistoryItem.Title)
+                    if (parent != null && parent.Name == sabHistoryItem.Title)
                     {
                         historyItem.OutputPath = parent.FullName;
                     }

src/NzbDrone.Core/Download/Clients/Sabnzbd/SabnzbdProxy.cs

@@ -6,7 +6,6 @@ using NzbDrone.Common;
 using NzbDrone.Common.Extensions;
 using NzbDrone.Common.Serializer;
 using NzbDrone.Core.Download.Clients.Sabnzbd.Responses;
-using NzbDrone.Core.Instrumentation.Extensions;
 using RestSharp;
 
 namespace NzbDrone.Core.Download.Clients.Sabnzbd