host/cli: Delete job/volume records during bootstrap
host/cli: Delete job/volume records during bootstrap

The controller stores various records about jobs and volumes in its
database during normal operation, and these records are stored in
cluster backups. When starting a new cluster, these records are no
longer needed and the stale volume records can cause the scheduler
to get confused if hostnames are reused.

This patch deletes all old job and volume events, job/volume
associations, jobs, and volumes from the controller database during
bootstrap.

Signed-off-by: Jonathan Rudenberg <3692bfa45759a67d83aedf0045f6cb635a966abf@titanous.com>

flynn/flynn,philiplb/flynn,lmars/flynn,lmars/flynn,flynn/flynn,flynn/flynn,philiplb/flynn,flynn/flynn,lmars/flynn,philiplb/flynn,philiplb/flynn,philiplb/flynn,lmars/flynn,flynn/flynn,lmars/flynn