scripts/firefox-gen-l10n-recipes: Stop using PRINC

Signed-off-by: Otavio Salvador <otavio@ossystems.com.br>
firefox-l10n-*: Drop PRINC use

This removes all PRINC use from firefox-l10n packages.

Signed-off-by: Otavio Salvador <otavio@ossystems.com.br>
firefox-addon-webconverger: Stop using PRINC

Signed-off-by: Otavio Salvador <otavio@ossystems.com.br>