MDL-73923 tool_task: make a more relaxed check on cron run interval
Prior to this change, the tool_task_cronrunning check had very tight
limits for checking the last cron interval and comparing it to the
expected frequency. When a cron job should take 1:00 min and the last
run was 1:02 min it complained that there was 1:02 between the last two
runs of the cron maintenance script and it should run every 1:00.
This change makes the check a bit more relaxed and adds an additional
minute on top of the expectedfrequency to give the cron job some time.
Signed-off-by: Daniel Ziegenberg <daniel@ziegenberg.at>