Pull region/auth url information from context.

def parse_region(self):
        """Pull region/auth url information from context."""

        try:
            auth_url = self.job_args['os_auth_url']
            if 'tokens' not in auth_url:
                if not auth_url.endswith('/'):
                    auth_url = '%s/' % auth_url
                auth_url = urlparse.urljoin(auth_url, 'tokens')
            return auth_url
        except KeyError:
            raise exceptions.AuthenticationProblem(
                'You Are required to specify an Auth URL, Region or Plugin'
            )