dockerfile: upgrade to `sameersbn/ubuntu:14.04.20151117`
dockerfile: upgrade to `sameersbn/ubuntu:14.04.20151117`

otsuka512/docker-redmine,otsuka512/docker-redmine,sameersbn/docker-redmine,otsuka512/docker-redmine,sameersbn/docker-redmine,sameersbn/docker-redmine