Allow for custom endpoint urls for non-AWS (testing and bootleg cloud) deployments

def configure_boto_session_method_kwargs(self, service, kw):
        """Allow for custom endpoint urls for non-AWS (testing and bootleg cloud) deployments"""
        if service in self.endpoint_urls and not 'endpoint_url' in kw:
            kw['endpoint_url'] = self.endpoint_urls[service]
        return kw