Updated mediawiki/extensions
Project: mediawiki/extensions/WikibaseDataModel  0879f2216d2fed0d0a389486ab3be9f34815a67f

Remove redundant methods from ItemDiff.

IMPORTANT: needs I0539c43fe in Wikibase, which removed usage of these methods.

Change-Id: I0c130c00023956d607ef323ccc2785c1453f1e37