credentials always return as invalid

Using the nova.sh script from cloudbuilders, I've set up nova+keystone+glance+dashboard. When running the combined set, the keystone service always refuses credentials. I set a breakpoint and inspected, and the error is in keystone/keystone/logic.py - under IdentityService.authenticate()

At line 41, it checks to make sure the credentials are a subclass of auth.PasswordCredentials. When I inspected the actual objects, it failed because it appeared to be a subclass of a different object (different pathing intereferred):

```python
{"passwordCredentials": {"username": "joeadmin", "password": "secrete", "tenantId": ""}}
> /home/ubuntu/keystone/keystone/keystone/logic/service.py(43)authenticate()
-> if not isinstance(credentials, auth.PasswordCredentials):
(Pdb) credentials
<keystone.keystone.logic.types.auth.PasswordCredentials object at 0x22d24d0>
(Pdb) auth.PasswordCredentials
<class 'keystone.logic.types.auth.PasswordCredentials'>
(Pdb)
```
The isinstance will fail because the credentials passed into the method are "keystone.keystone.logic.types.auth.PasswordCredentials", not "keystone.logic.types.auth.PasswordCredentials".