Check minimum database server version when running update.php

If MediaWiki has increased the minimum database server version that is
required, check it when running update.php to ensure it is still
compatible. Previously this was only checked during the installer.

Bug: T162044
Change-Id: I47092c9557f4706a4dcb3a23150647e68af4317f
(cherry picked from commit 574ae4929e30700e29fef0e0d4f4824599205174)