Cleanup ignat99 feat

New PR from https://github.com/Ignat99/OpenBazaar/pull/1 directly into OpenBazaar:develop.
No, this not the equivalent. Here's the original code in one line:
```python
settings['privkey'] = settings['privkey'] if 'secret' in settings else ''
```
The presence of `settings['secret']` is important; its value is not.