Updated mediawiki/extensions
Project: mediawiki/extensions/Wikibase  64714e0d28a5750ab3fe863e070c0278d1b5a43f

(testing) adjusted selenium test to check for changed error msg

- error message for edit conflicts has changed, so test needs to be
  adjusted

Change-Id: Ib69f231c1057845ef15e0b099c1412fd0c70c7e3