Tear down the instance

def tear_down(self):
        """Tear down the instance
        """
        import boto.ec2

        if not self.browser_config.get('terminate'):
            self.warning_log("Skipping terminate")
            return

        self.info_log("Tearing down...")

        ec2 = boto.ec2.connect_to_region(self.browser_config.get("region"))
        ec2.terminate_instances(instance_ids=[self.instance_id])