Additional Instance that is same name with already existing instance can be created

[TsutomuNakamura]

An instruction is already checking whether the instance existed. But the instruction is wrong...

https://github.com/tsuna-server/build-server-ansible/blob/990addbe8e6ef6cf28fb444ff48ad462f7458e30/roles/test_env/tasks/create_example_cirros/main.yml#L45-L48