Updated mediawiki/extensions
Project: mediawiki/extensions/Wikibase  5d388e2d1d9acea8cf98b5b015aa765101800348

Create ChangeOpReferenceRemove class.

This simplifies ChangeOpReference by removing the
remove function and putting it in a seperate class
as suggested on...
https://gerrit.wikimedia.org/r/#/c/106897/3/repo/includes/ChangeOp/ChangeOpReference.php

Tests are also included in this changeset as well
as switching all usage of the old changeop to remove
references to use the new changeop

Change-Id: I79304c6235a28dda13bdfc5ba0a6908eec683cea