Mihail Geshoski authored Nov 27, 2020 and Jake Dallimore committed Jan 13, 2021

Prevents configuring the 'Data modification API' (convert_data) setting
to use files located within the $CFG->dataroot directory as it exposes
the site to security risks.

This reduces the amount of code to an already confusing logout.php
file and prevents conflicts if someone else happens to be using
the same function name in a file.