Fix bug 1346150: Fix regression (#594)
Fix bug 1346150: Fix regression (#594)

A regression was introduced by the previous change in sorting of the
latest activity column.
mathjazz/pontoon,mastizada/pontoon,mastizada/pontoon,mozilla/pontoon,mathjazz/pontoon,jotes/pontoon,mozilla/pontoon,jotes/pontoon,mathjazz/pontoon,jotes/pontoon,mastizada/pontoon,mozilla/pontoon,mozilla/pontoon,mozilla/pontoon,mastizada/pontoon,mathjazz/pontoon,jotes/pontoon,mathjazz/pontoon