SecurityWorker fails when indexing a manifest layer's location is remote

securityworker stdout | 2021-07-19 19:05:56,467 [113] [DEBUG] [data.secscan_model.secscan_v4_model] Indexing 302/microsoft-dotnet-framework@sha256:dbfad8d5e0fffbd6f2f3cab58b4012156827e205388091c859650b33b51a4782
securityworker stdout | 2021-07-19 19:05:56,468 [113] [DEBUG] [data.database] Disconnecting from database.
securityworker stdout | 2021-07-19 19:05:56,468 [113] [ERROR] [workers.worker] Operation raised exception
securityworker stdout | Traceback (most recent call last):
securityworker stdout |   File "/quay-registry/workers/worker.py", line 87, in _operation_func
securityworker stdout |     return operation_func()
securityworker stdout |   File "/quay-registry/workers/securityworker/securityworker.py", line 32, in _index_in_scanner
securityworker stdout |     self._next_token = self._model.perform_indexing(self._next_token)
securityworker stdout |   File "/quay-registry/data/secscan_model/__init__.py", line 43, in perform_indexing
securityworker stdout |     return self._model.perform_indexing(next_token)
securityworker stdout |   File "/quay-registry/data/secscan_model/secscan_v4_model.py", line 286, in perform_indexing
securityworker stdout |     (report, state) = self._secscan_api.index(manifest, layers)
securityworker stdout |   File "/quay-registry/util/secscan/v4/api.py", line 180, in index
securityworker stdout |     "layers": [
securityworker stdout |   File "/quay-registry/util/secscan/v4/api.py", line 183, in <listcomp>
securityworker stdout |     "uri": self._blob_url_retriever.url_for_download(manifest.repository, l.blob),
securityworker stdout |   File "/quay-registry/util/secscan/blob.py", line 33, in url_for_download
securityworker stdout |     uri = self._storage.get_direct_download_url(self._storage.locations, blob.storage_path)
securityworker stdout | AttributeError: 'NoneType' object has no attribute 'storage_path'
securityworker stdout | 2021-07-19 19:05:56,468 [113] [INFO] [apscheduler.executors.default] Job "SecurityWorker._index_in_scanner (trigger: interval[0:00:30], next run at: 2021-07-19 19:06:26 UTC)" executed successfullyservicekey stdout | 2021-07-19 19:05:56,878 [114] [DEBUG] [util.metrics.prometheus] pushed registry to pushgateway at http://localhost:9091 with grouping key {'host': 'registry-quay-app-56ff5dc5f5-k45g8', 'process_name': 'servicekeyworker.py', 'pid': '114'}