Prevent deleteBatch.php deleting files from redirects

Previous behavior had the maintenance script deleteBatch.php
delete both the redirect in the file namespace and the file
from the target page the redirect is pointing to. This is
no longer the case, but it will still delete the redirect
page if it is still on the listfile.

Bug: 52587
Change-Id: I83374ddb98131f9f8f766bb2b444ab3e7cda7735
Merge "Prevent deleteBatch.php deleting files from redirects"