Update mm.inc.php

fix for correct work 
http://monosnap.com/image/DuBhZa05oUUx5yWquz6w6IGniSIk0l

for this commit 
https://github.com/dmi3yy/modx.evo.custom/commit/7ca78a969b52953c718353845ebaa2c967e29a4c