in local development, zip uploads are broken

```
| File "/build/clusterfuzz/src/appengine/handlers/jobs.py", line 132, in post
| blob_info = self.get_upload()
| File "/build/clusterfuzz/src/appengine/handlers/base_handler.py", line 317, in get_upload
| blob_info = storage.GcsBlobInfo.from_key(upload_key)
| File "/build/clusterfuzz/src/python/google_cloud_utils/storage.py", line 556, in from_key
| logs.log_error('Failed to get blob from key %s.' % key)
| LogError: Failed to get blob from key 0e3179ad-31b4-4ba5-a45c-86a610e065c7.
| Traceback (most recent call last):
| File "/build/clusterfuzz/src/python/google_cloud_utils/storage.py", line 554, in from_key
| return GcsBlobInfo(blobs_bucket(), key)
| File "/build/clusterfuzz/src/python/google_cloud_utils/storage.py", line 536, in __init__
| self.filename = gcs_object['metadata'].get(BLOB_FILENAME_METADATA_KEY)
| TypeError: 'NoneType' object is not subscriptable
```