Run self-destruct on every 0th worker
Run self-destruct on every 0th worker

If the master is dead for some reason, we still want to collect the cluster.
There is precedent for sed/grep/etc against the pattern in many repositories
on github, thus I do not expect the pattern to change... :|
This is a bashism, yuck (as is this whole file)

spotify/spydra,spotify/spydra,spotify/spydra