Updated mediawiki/extensions
Project: mediawiki/extensions/Wikibase  8be6e35c9254e78fd7e1322f42424a7555cb8e5b

Remove reference to removed UnserializerBaseTest class

In 5a4f58434cacd1bc0189757e56975f5030b37ff7, the class UnserializerBaseTest
was removed. This removes its entry in WikibaseLib.classes.php.

Change-Id: Ibbd8fda763378a64a929ffe588f18657ca35910d