Updated mediawiki/extensions
Project: mediawiki/extensions/PageCreationNotif  da151b72fd188204dea5373dfa673bb9304103f4

Added checks and updated README

added an extra check, otherwise a NOTICE would show on user creation.
Updated readme to add missing step: update.php

Change-Id: I0dcf6a5ee489c4b9c7e834fbb9cccd0ab895e70d