Update ArticleSaved hook to use correct request object

'Revert' via the API apiEditPage.php does not trigger reverted notification, this is probably due to the fake request object swap inside this API, which is making the param wgUndidRevision with empty value inside the hook, replace $user->getRequest() with $wgRequest solves this problem.

Change-Id: I5d12d31f370f2633e85d6533242da26ece950630