- Make sure we log when an exception occurs in the squashing code

- Have queue file always try to return any remaining data in the buffer
- Remove the raise of the exception when we get an empty tar file

endpoints/verbs.py

@@ -49,6 +49,7 @@ def _write_synthetic_image_to_storage(linked_storage_uuid, linked_locations, que
   store = Storage(app)
 
   def handle_exception(ex):
+    logger.debug('Exception when building squashed image %s: %s', linked_storage_uuid, ex)
     model.delete_derived_storage_by_uuid(linked_storage_uuid)
 
   queue_file.add_exception_handler(handle_exception)