What if we drop ChangeLog.pre-1-22, keep ChangeLog and add a note to it stating the GIT revision where ChangeLog.pre-1-22 can be found?
I would still prefer keeping it. Apart from changelog it's an easy-to-access source of credits and "who did what" before git was introduced. After git, you can easily see all the contributors and their patches by selecting the "Contributors" link on github. If we remove the file and only link to a past commit which contains it, there won't be any easy way to access it while browsing github.