There is a new init sequence that is executed prior to all concurrent
init.d services.
Placing ordered services in /etc/boot.d allows you to interpose upgrade,
verification, and special handling prior to execution of the normal SYSV init.
This system can be accessed by placing ordered scripts directly in
/etc/boot.d from your package.
This infra is used to perform early loader and partition upgrade checks, onie upgrades,
cpld upgrades, and the like.
Normal filesystem mounts are performed at priority 50.
Platform initialization is performated at priority 51.
TODO: Integrate upgrade sequence.
