Bug 1018724 - Tabzilla lang bar broken

A workaround for the wrong language detection due to caches, until the
header issue is fixed by CDN.
[fix bug 1010519] - usage campaign add descriptive text to learn more links
Merge pull request #2069 from kyoshino/bug-1018724-wrong-tabzilla-lang

Bug 1018724 - Tabzilla lang bar broken
Merge pull request #2072 from alexgibson/bug-1010519-usage-campaign-add-descriptive-text-learn-more-links

[fix bug 1010519] usage campaign add descriptive text to learn more links