The node-engine writes a cron step (*/15) as a calendar systemd refuses, so
zfs-mesh-scrub.timer never started and the pool had no scrub schedule. A list
of minutes is written as *-*-* *:0,15,30,45:00, which systemd takes.
Builds: design 42 zfs-owns-zfs §18. Tests: 1979/AC1.
jschoubben