'To GET Details of a credential.
For a full list of available parameters, please refer to the official
API reference:
http://developer.openstack.org/api-ref/identity/v3/index.html#show-credential-details'

def show_credential(self, credential_id):

    (resp, body) = self.get(('credentials/%s' % credential_id))
    self.expected_success(200, resp.status)
    body = json.loads(body)
    return rest_client.ResponseBody(resp, body)
