The previous saving throw limit (3/15s) seems to have been too low. I
was observing bizarre failures where a node would be fenced while it was
still starting up. Some of this may have been related to Zookeeper
connections taking too long, but this was inconsistent.
Increase this to 6 saving throws (30s). This provides significantly more
time for a node to properly check in on startup before another node
fences it. In the real world, 15s vs 30s isn't that big of a downtime
change, but prevents false-positive fences.