Updated mediawiki/extensions
Project: mediawiki/extensions/Parsoid  8da18bb8438a7c71beb35a41ebac861285b3d3ef

Apply the same fix in 5ff4ad75 for /_rt/ endpoint

* This will let us duplicate errors on localhost and the wmflabs
  install of parsoid -- useful for debugging.

Change-Id: If4d71b1c24c66d3732032dab5c5fb2079d9ccb28