fix(core): missed portable var rename

Author: Xjph

ObservatoryCore/PluginManagement/PluginCore.cs

@@ -311,9 +311,9 @@ private void MigratePluginStorage(string oldKey, string newKey, Guid guid)
 #if PORTABLE
             // Plugin subfolder portable storage migration
             var legacyPortablePath = GetLegacyStorageFolder(oldKey);
-            if (Directory.Exists(legacyPortablePath) && !Directory.Exists(newPath))
+            if (Directory.Exists(legacyPortablePath) && !Directory.Exists(newDir))
             {
-                MoveDirectoryWithCleanup(legacyPortablePath, newPath);
+                MoveDirectoryWithCleanup(legacyPortablePath, newDir);
             }
 #endif 
         }