staging: keucr: fix keucr lost disconnect in transport

The other part of keucr lost usb disconnect.
Unplug SDcard after thread scan,the wrong rule in usb_stor_port_reset,
so the driver still fail in stress test.

Signed-off-by: Al Cho <acho@novell.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>