'Call ``GET /users`` making sure no default_project_id.'

def test_list_users_no_default_project(self):

    user = unit.new_user_ref(self.domain_id)
    user = self.identity_api.create_user(user)
    resource_url = '/users'
    r = self.get(resource_url)
    self.assertValidUserListResponse(r, ref=user, resource_url=resource_url)
