When we send a stop unit command to a device, send it as an ordered tag so that any transactions in front of the stop command get flushed to disk first.  This will have no effect on devices that have tagged queueing turned off, or don't support tagged queueing.
When we send a stop unit command to a device, send it as an ordered tag so
that any transactions in front of the stop command get flushed to disk
first.  This will have no effect on devices that have tagged queueing
turned off, or don't support tagged queueing.

Reviewed by:	gibbs

jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase