[RELENG_6] ATARAID oddity

[Dieter]

> I.e. if you insert a drive that was part of a volume from an Adaptec 
> RAID controller into another system, the new system will attempt to 
> treat that disk as though it were associated with a HOST Raid controller.
> 
> I don't think that this is the desired behavior.  Even if the host raid 
> meta-data is detected, the system shouldn't attempt to treat the disk as 
> part of a HOST raid set without the appropriate controller in the system.

Even if there *is* an appropriate controller in the system, presumably it
isn't going to work unless the disk is connected to that controller.

We want the ability to migrate a disk from Adaptec to some other
controller without screwy things happening.