fix block timeout residue problems

It looks like there was only a partial conversion of the SCSI layer to the block timeout. The missing piece was killing timeout in struct scsi_device and leaving it with a zero value. This has already resulted in a regression:

http://bugzilla.kernel.org/show_bug.cgi?id=12120

But on closer inspection, there were lots of other dangling driver uses of the timeout value which would likewise have introduced hard to trace regressions.

This patch series eliminates the timeout variable from struct scsi_device and makes everything uniformly use the block timeout. Any wrong use of the scsi device timeout will now result in a compile failure.

It's getting late in the -rc series to push this through, but hopefully it won't delay 2.6.28 too much.

James