Open Local File on OpenFile When No Object Exists

[foodprocessor]

✅ What

• Actually open a local file in OpenFile if there is no object in cloud storage
• Rename downloadFile to openFileInternal
• Acquire lock before calling openFileInternal, to allow OpenFile to call it as well
• Check that openComplete is false before acquiring a lock and calling openFileInternal, to prevent performance issues

🤔 Why

1. If there is no object to download, there is no performance penalty for opening the file completely.
2. Without this change, if an application calls Open to create a new file, and then checks if that file exists, we would return ENOENT!