dockerio state: avoid shadowing running() func

```
salt/states/dockerio.py:398: [W0621(redefined-outer-name), absent] Redefining name 'running' from outer scope (line 524)
salt/states/dockerio.py:561: [W0621(redefined-outer-name), running] Redefining name 'running' from outer scope (line 524)
```