Revert "Bug 893006 - change the rewrite rule for firefox/update to take locales into account if we have a translation"

This reverts commit 010175bb728f86c859971dd8e9614e599111b77a.
Undo "Revert "Bug 893006 - change the rewrite rule for firefox/update to take locales into account if we have a translation""

This reverts commit 0760ec64a7b8bf430a5aa13602c37a3501488100.
[Bug 894074] stop redirecting old versions to firefox.update until it's localized