Updated mediawiki/extensions
Project: mediawiki/extensions/GlobalUsage  0eafc4db08a4b4cb30b7d3d06566dfcab48a284d

Added support for purging backlinks in the wiki farm

* This adds a $wgGlobalUsageSharedRepoWiki and a $wgGlobalUsagePurgeBacklinks variable
* This works by pushing jobs on the repo wiki that push HTMLCacheUpdateJob jobs on all
  the client wikis for the imagelinks table

bug: 22390
Change-Id: Ib764e9774d208a8b20d4d67db229c24fd21734c8