Description of problem:

I've ended up with a couple of instances in STATE_ERROR that I couldn't delete from the web UI.  The current test for whether or not an instance (and thus the deployment) is destroyable is this:

(state == STATE_CREATE_FAILED) or (state == STATE_STOPPED and not restartable?)

Is there any reason that we shouldn't include instances in the STATE_ERROR state?

Version-Release number of selected component (if applicable):
aeolus-conductor-0.3.0-0.el6.20110707201945gitc26c54e.noarch

How reproducible:
100%

Steps to Reproduce:
1. Try to delete a deployment which has instances in the STATE_ERROR state.
  
Actual results:
Error.

Expected results:
Deployment is deleted.