Memory leak in Filterindex / ServiceRegistryCache

The filter indexes in the ServiceRegistryCache caches ServiceListeners for a faster lookup.
However, once a ServiceListener is stored in the cache, it will never be released which will eventually lead to an OutOfMemoryError.

This is caused by the implementation of BundleContextIntercepter#removeServiceListener.
While debugging, it appears the cache has no filterindex for arguments null,null and thus leaving the listener in the cache.