Updated mediawiki/extensions
Project: mediawiki/extensions/Wikibase  7e0eea5bbe36519932789571f3e8055554b8dddb

Fix various issues with test cases.

* Invalid capitalization of class names (fatal error)
* Failure to use @group Datatbase (fatal if no DB is present)
* Make base classes abstract
* Documentation fixes

Change-Id: I918ab013b668a88489d944d4fa55148cbd24c79f