Bug 1785985: Offset the problematic cron jobs

As mentioned in forum post
https://mahara.org/interaction/forum/topic.php?id=8450#post33705



behatnotneeded

Change-Id: I700c295d6d4ced232a119c3f8dbbc922a73298d3
Signed-off-by: Robert Lyon <robertl@catalyst.net.nz>