Fixed duplicate UpdateHistory items

(cherry picked from commit ad9e709d96a4c8635f52e9ee8623fa805e628de6)

src/NzbDrone.Core/Update/History/UpdateHistoryRepository.cs

@@ -25,7 +25,7 @@ namespace NzbDrone.Core.Update.History
         public UpdateHistory LastInstalled()
         {
             var history = Query(x => x.EventType == UpdateHistoryEventType.Installed)
-                               .OrderBy(v => v.Date)
+                               .OrderByDescending(v => v.Date)
                                .Take(1)
                                .FirstOrDefault();
 
@@ -35,7 +35,7 @@ namespace NzbDrone.Core.Update.History
         public UpdateHistory PreviouslyInstalled()
         {
             var history = Query(x => x.EventType == UpdateHistoryEventType.Installed)
-                               .OrderBy(v => v.Date)
+                               .OrderByDescending(v => v.Date)
                                .Skip(1)
                                .Take(1)
                                .FirstOrDefault();