Bug 1069227 - [Loop] Make sure that we recover from an expired token situation

See bug https://bugzilla.mozilla.org/show_bug.cgi?id=1069227 please.
Actually, I think this is going to be a weird UX. Isn't `AccountHelper.logout` kicking the user out of the app and placing her into the login screen? Could you also check this with UX, please?