Remove the  hadolint ignore lines from the Dockerfile

Improve [Dockerfile](https://github.com/kksudo/odyssey-docker/blob/master/Dockerfile) to pass the "lint" and "shellcheck" through [hadolint](https://github.com/yandex/odyssey) without warnings.
[Example](https://github.com/hadolint/hadolint/blob/master/docker/Dockerfile)