Fixed: Allow repeated import attempts until downloaded files appear

(cherry picked from commit 9f1d4446e82e9c5efde3d0339be2f7dde40ba1ac)

src/NzbDrone.Core/Download/CompletedDownloadService.cs

@@ -95,6 +95,7 @@ public void Import(TrackedDownload trackedDownload)
             if (importResults.Empty())
             {
                 trackedDownload.Warn("No files found are eligible for import in {0}", outputPath);
+                trackedDownload.State = TrackedDownloadState.ImportPending;
                 return;
             }