LGTM Just two thoughts:
1. I'm not sure why you suggest how to set the root password, as the dev user can get admin privileges via sudo. 2. While keyboard configuration is a step needed for any non-US contributor, reconfiguring the locales should be useful only for translators, unless I miss something. Perhaps you could say that these two configurations are optional. https://codereview.appspot.com/561360043/
