[PATCH] init: Add handshake to poweroff/reboot for signal handler setup

[Deb McLemore]

The abstract socket is the indicator that the state of Busybox is ready to accept the

signal that triggers the Busybox poweroff sequence, this handshake between the kernel userhelper

and Busybox is indicator that Busybox is ready to accept the signal and then process

the signal properly is the linkage desired (otherwise windows are still exposed).