Syncronize VisualEditor: 400a522..eb10020

Change-Id: Idbb6b9c2d6d7993cb4919d9292d8d04eb17020c9
Updated mediawiki/extensions
Project: mediawiki/extensions/CentralAuth  72055f0fe7217830dcecb448087b7d215e48cf96

Die gracefully if CentralAuthUser class doesn't exist

Seems counterintuitive, but if you're running it say over all
Wikimedia wikis (to create accounts for Stewards for example),
numerous private wikis etc do not have CentralAuth.

Change-Id: I6b44b38cfb10e93e999eecbe6ebaa36fe34728e0