Issue 3681 update l10n env

@ozten mind reviewing? don't want to commit this, just looking for feedback.

I've updated the post-deploy script ([8bd6e6](https://github.com/6a68/browserid/commit/8bd6e6))) to use `scripts/l10n-update` instead of `compile-json.sh` in the svn repo.

I think we still need the [update-translations](https://github.com/6a68/browserid/blob/8bd6e6/scripts/update_translations.sh) script, which does bookkeeping stuff like appending the svn info to `ver.txt`--but is there anything else I've missed?