setFacility with a number <> string

Hi,
(maybe it's something I did not understand in the docs)

I need to log to local3.info

This code does not work:

```
syslog.setFacility(3)
syslog.info('test')
```

This one does:

```
syslog.setFacility('local3')
syslog.info('test')
```
