Improve handling of 0x3F/0x0E "Reported LUNs data has changed" and 0x25/0x00
"Logical unit not supported" errors.  First initiates specific target rescan,
second -- destroys specific LUN.  That allows to automatically detect changes
in list of device LUNs.  This mechanism doesn't work when target is completely
idle, but probably that is all what can be done without active polling.

Reviewed by:	ken
Sponsored by:	iXsystems, Inc.