Google Code-in

Your task is to fix the issue set out in https://phabricator.wikimedia.org/T65010.

To test whether you have fixed the bug:

• Create a file on your hard disk that contains just the character 9 with no newline at the end. This file has a SHA1 hash starting with 0.
• Save the file with a .txt extension.
• Enable uploading on your local test MediaWiki installation and add txt to the list of allowed file extensions (see documentation on MediaWiki.org)
• Upload your test file to the wiki
• Run the dumpBackup command line written in the Phabricator task
• Delete the test file from the wiki
• Run the importDump command line written in the Phabricator task
• Browse to your file's location on the wiki, see whether it says "no file exists" (bug) or lets you download the text file (no bug)