Updated mediawiki/extensions
Project: mediawiki/extensions/UploadWizard  a1d94b998641f357261990f5d4365c346fd00299

(bug 38470) Better message for filename already in use.

Guide the user to forward by suggesting how to solve the problem.

Change-Id: Ibb701fde88ed00a3ab6836a4dd2b2df1a13ea9b8