Introduce an rc.d service to upgrade packages on first boot, ensuring
cloud images are deployed with no known vulnerabilities. By default,
it will patch everything from all enabled repos, and record this in
syslog. It accepts an optional additional line that specifies a list
of space-separated specific repos to upgrade.
Note specifying bogus repos result in the upgrade aborting, and it will
not run again.
Sponsored by: Google
Discussed with: bapt, cperciva, delphij