should use password provided by API if it isn't specified in the configu...

...ration file.

When provisioning Windows Servers with salt-cloud, they should attempt to login using the password returned by the API, not a hard coded value from the configuration file.

This is my attempt at fixing this issue for the Rackspace Cloud. I'm not 100% on the testing process for this change, so please examine carefully the impact of my small change.