Fix output issues on Rollback

Capability to use output values during a Rollback scenario

See the example, now it is working

 result = spintest(
        ["http://test.com"],
        [
            {
                "method": "GET",
                "route": "/test",
                "output": "test_output",
                "expected": {"code": 400},
                "rollback": ["test_rollback"],
            },
            {
                "name": "test_rollback",
                "method": "DELETE",
                "route": "/test/{{ test_output['id'] }}",
                "expected": {"code": 201},
            },
        ],
    )