RAIDframe: reconstucting a temporarily lost drive (was: SATA rescan)

[Edgar Fuß <ef%math.uni-bonn.de@localhost>]

> drvctl -r -a ata_hl atabusX
OK, that (after moving to a different slot) brought the drive back again.

However, the raid had failed the missing drive (whether upon booting with 
the missing drive or shortly before the crash I can't tell). I had /dev/wd0a 
optimal plus component1 failed. I guess there's no way to teach RAIDframe 
the missing drive is back (short of rebooting, which is out of the question)?

I added /dev/wd1a as a spare and failed component1, which worked, but maybe 
there's a more elegant way?