When sg_scsi_ioctl() fails to prepare request to submit in
blk_rq_map_kern() we jump to a label where we just end up copying
(luckily zeroed-out) kernel buffer to userspace instead of reporting
error. Fix the problem by jumping to the right label.

CC: Jens Axboe <axboe@kernel.dk>
CC: linux-scsi@vger.kernel.org
CC: stable@vger.kernel.org
Coverity-id: 1226871
Signed-off-by: Jan Kara <jack@suse.cz>

Fixed up the, now unused, out label.
Signed-off-by: Jens Axboe <axboe@fb.com>