Code review comment for lp:~bzoltan/click/vivid-transition_mirrors

Feedback and summing-up of irc discussion

Ubuntu users are suggested to use [countrycode].archive.ubuntu.com, but most users will select a random mirror server from the software center config (software-properties) or intstaller. http://i.imgur.com/2EvQIrv.png It ends up the user will not have xx.archive.ubuntu.com in /etc/apt/sources.list as reference.

It would make more sense that user can pick a mirror server during the new `click root` setup
1. A dialogue for user to pick which mirror to use. [countrycode].[ports|archive].ubuntu.com
2. The dialogue should suggest the default or preferred mirror server for the user. software-properties use user's locale to guess where is the most close mirror site.

Please note only [countrycode].[ports|archive].ubuntu.com are guarantee up-to-date, the other mirror can delay for few weeks. So we only use [countrycode].[ports|archive].ubuntu.com for phone developer.