Do not make the ingest folder

A folder that Bindery made hid a missing volume mount. The books went
to a folder inside the container, and CWA never saw them. A missing
folder is now an error in the log at the start, and each upload fails
with a message that names the mount.

tests/test_deliver.py

@@ -35,6 +35,7 @@ def fake(story_epub, monkeypatch, tmp_path):
     monkeypatch.setattr(config, "CWA_PASSWORD", "secret")
     monkeypatch.setattr(orchestrator, "store", Store(tmp_path / "bindery.db"))
     monkeypatch.setattr(config, "INGEST_DIR", tmp_path / "ingest")
+    config.INGEST_DIR.mkdir()
     monkeypatch.setattr(orchestrator, "finder", orchestrator.BookFinder())
     yield server
     server.close()