Revert "Update Wikidata to master"

mergeMessageFileList.php failed with 

PHP Warning:  Class 'Wikibase\DataModel\Entity\Item' not found in /a/common/php-1.23wmf12/extensions/Wikidata/vendor/wikibase/data-model/WikibaseDataModel.php on line 35

etc.

This reverts commit 2d89b19744e40151cc6ec5bbd98ce12e40afd2d2.

Change-Id: I1364bfc86dca535df359ab69ea817e7cd6b1865a