Add docker_opts setting to docker_daemon.
docker_daemon: add pull_images option
bootstrapvz/plugins/docker_daemon: flake8
bootstrapvz/plugins/docker_daemon: spaces to tabs
plugins/docker_daemon: logcheckcall, inline pull and indent
plugins/docker_daemon: align with space
plugins/docker_daemon: only add PullDockerImages tasks when pull_images is set
plugins/docker_daemon: flake8
fix ident, raise TaskError
docker_daemon: add comments