gstelementfactory: Fix missing features in case a feature moves to another filename
In case a plugin filename was renamed with the plugin being in the registry cache the features were not loaded after the rename:
- Cache of old/gone filename was loaded, features added
- New filename was loaded, features where not added because they were already found in the registry.
- In the end stale cache entries for files which are no longer there are removed, including the wanted features.
- The cache gets updated without the features.
Fix this by also checking at (2) that the found feature is from the loaded plugin and not from some stale cache entry.
This affected directsoundsink where libgstdirectsoundsink.dll was renamed to libgstdirectsound.dll, losing the directsoundsink element in the process.