Updated mediawiki/extensions
Project: mediawiki/extensions/Wikibase  4d50cb6fa1027bd253543c572d212aef5d771d2b

Hotfix: Make Special:SetSiteLink not set already used Links

Besides: fixed edit link in ItemView class to Special:SetSitelink

This leaves error message parsing slightly broken, but
that's a different matter.

Change-Id: Iaa3d0718efa34db08c770ca1eb768560ff0e37a0