Revert "Fail gracefully if people are using older MW"

Causes problems when $wgVersion = '1.22wmf21'

This reverts commit 67e1be7bdc003cef1686ff73bba8352ed2436b03.

Change-Id: Ide534efd1ae5cf40ae10b5b17428c6ddd87985b7
Merge "Revert "Fail gracefully if people are using older MW""