[PATCH] usb-storage: catch bad commands

[PATCH] usb-storage: catch bad commands

The purpose of this patch is to trap all commands which have a bogus
request_bufflen.  Much logic is devoted to calculating the proper length of
the transfer, but according to discussions I've had on linux-scsi, this is
really a bug in whatever is originating the bad command.

Hopefully, after people use this patch for a while, we'll eliminate all the
offending sources and can remove quite a bit of logic from the driver.