in __scsi_add_device, sdev may be uninitialised if
scsi_host_scan_allowed() returns false.  Fix by initialising at the
top of the routine.  Also rely on the fact that
scsi_probe_and_add_lun() only actually fills in the sdev pointer if
the SCSI_SCAN_LUN_PRESENT case (so no need to check the return value).
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>