around. If the kernel boots successfully, the record of this kernel
is erased, it is intended to be a one-shot option for testing
kernels.
This could be improved by having the loader remove the record of
the next kernel to boot, it is currently removed in /etc/rc immediately
after disks are mounted r/w.
I'd like to MFC this before the 4.6 freeze unless there is violent
objection.
Reviewed by: Several on IRC
MFC after: 4 days
9bf40bea60