AttributeError on sitePublish on Linux

```
- Libsecpk256k1 loaded: CompiledLib in 0.028s
- Version: 0.7.1 r4206, Python 3.7.3 (default, Mar 27 2019, 22:11:17)
[GCC 7.3.0], Gevent: 1.4.0
SiteManager Deleting orphan site from content.db: 1Name2NXVi1RDPDgf5617UoW7xA6YrhM9F
SiteManager Deleting orphan site from content.db: 1DvxA4WP2jbBaZbTebV1RufMLhTTqDhVUQ
- Loading site...
- Unhandled exception: 'NoneType' object has no attribute 'settings'
Traceback (most recent call last):
File "/builds/wizardforcel/zeronet-uploader/ZeroNet-linux-dist-linux64/core/zeronet.py", line 17, in main
main.start()
File "/builds/wizardforcel/zeronet-uploader/ZeroNet-linux-dist-linux64/core/src/main.py", line 537, in start
actions.call(config.action, action_kwargs)
File "/builds/wizardforcel/zeronet-uploader/ZeroNet-linux-dist-linux64/core/src/main.py", line 121, in call
back = func(**kwargs)
File "/builds/wizardforcel/zeronet-uploader/ZeroNet-linux-dist-linux64/core/src/main.py", line 381, in sitePublish
site.settings["serving"] = True # Serving the site even if its disabled
AttributeError: 'NoneType' object has no attribute 'settings'
```

Start in core/src/main.py at sitePublish, around line 381, and trace how the site object is obtained before its settings are accessed. Reproduce the sitePublish action on Linux with the reported environment and determine why it is None; done means the action completes without this AttributeError.

Rédigé par le modèle d'indexation à partir du texte de l'issue.