[SCSI] ipr: Disk remove path cleanup

Instead of NULLing the resource entry pointer when a disk
goes away to prevent any new commands being sent to it,
set the adapter resource handle to an invalid value so
new ops getting sent to it will fail with a selection timeout
response. This patch is needed for future SATA patches.

Signed-off-by: Brian King <brking@us.ibm.com>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>