Fix locales format based on wrong assumption
A few places in Tails (git grep LANG) assume everything that can be in
$LANG starts with the xx_XX form, which is, unfortunately, not true:
e.g. fil_PH.
Instead of relying home-made shell trickery and re-inventing the wheel we should consider using some existing library or tool for this, or we should read the standards so we can prevent buggy edge cases.
Related issues
- Related to #6142
- Related to #17002 (closed)
- Has duplicate #17003 (closed)
Original created by @tails on 6001 (Redmine)