Missing breadcrumb in mobile locale selection page

[scott]

The translation for the root breadcrumb is missing. Also, the link to go to this page should be hidden if there are no alternate translations.

[olliebennett]

As a quicker way to identify this more generally, how about forcing exceptions to be raised on missing translations?

Basically, we just need to uncomment the following in development.rb and test.rb:

# Raises error for missing translations
config.action_view.raise_on_missing_translations = true

More info here.