title: Can't upload files in Mediawiki
body: <p>After I've updated to Mediawiki 1.29.0, I can't upload any file. When I upload a file, I get this error message:</p>
  
  <p>Could not open lock file for "mwstore://local-backend/local-public/b/b0/1.jpg".</p>
  
  <p>I've chmod the folder images and sub-directories to 755, and verified that the folder images/b/b0 is found and writable.</p>
  
  <p>I'm running on Centos 7.5 and PHP 5.6</p>