fix: properly fetch the internal ip on ubuntu 18.04
fix: properly fetch the internal ip on ubuntu 18.04

progrium/dokku,dokku/dokku,claytonbrown/dokku,progrium/dokku,dokku/dokku,dokku/dokku,claytonbrown/dokku,claytonbrown/dokku,claytonbrown/dokku,progrium/dokku,claytonbrown/dokku,progrium/dokku,dokku/dokku,dokku/dokku,progrium/dokku,claytonbrown/dokku,dokku/dokku,progrium/dokku,claytonbrown/dokku,dokku/dokku,dokku/dokku,claytonbrown/dokku,progrium/dokku,progrium/dokku