This breaks backwards compatibility:

```
2013-08-15 16:58:41,649 [saltcloud.cli    ][ERROR   ] There was an error destroying machines: Dict object expected, not "'ZZZcent5525cb4 has been destroyed'".
Traceback (most recent call last):
  File "/usr/src/salt-cloud/saltcloud/cli.py", line 214, in run
    ret = mapper.destroy(names, cached=True)
  File "/usr/src/salt-cloud/saltcloud/cloud.py", line 407, in destroy
    ret = self.clouds[fun](name)
  File "/usr/src/salt-cloud/saltcloud/libcloudfuncs.py", line 298, in destroy
    event.fire_event('{0} has been destroyed'.format(name), 'salt-cloud')
  File "/usr/src/salt/salt/utils/event.py", line 256, in fire_event
    raise ValueError('Dict object expected, not "{0!r}".'.format(data))
ValueError: Dict object expected, not "'ZZZcent5525cb4 has been destroyed'".
```

At the bare minimum, there should be a big fat warning in the 0.17.0 release docs.