Fixed: Error logged when checking if v2+ anime release is a valid upgrade

Fixes #3114

src/NzbDrone.Core/DecisionEngine/Specifications/AnimeVersionUpgradeSpecification.cs

@@ -32,6 +32,11 @@ namespace NzbDrone.Core.DecisionEngine.Specifications
 
             foreach (var file in subject.Episodes.Where(c => c.EpisodeFileId != 0).Select(c => c.EpisodeFile.Value))
             {
+                if (file == null)
+                {
+                    continue;
+                }
+
                 if (_upgradableSpecification.IsRevisionUpgrade(file.Quality, subject.ParsedEpisodeInfo.Quality))
                 {
                     if (file.ReleaseGroup.IsNullOrWhiteSpace())