Updated mediawiki/extensions
Project: mediawiki/extensions/MobileFrontend  899db6fad1931e8695706bac74d86cbd028dc1cd

story 428: Log username for watch star and photo uploads

Depends on https://gerrit.wikimedia.org/r/51291 for latest schema

Change-Id: I950e4a04f7c2a511c9b2af38abfbad5f5fc853ee