[PATCH] blk: Fix SG_IO ioctl failure retry looping

When issuing an SG_IO ioctl through sd that resulted in an unrecoverable
error, a nearly infinite retry loop was discovered. This is due to the
fact that the block layer SG_IO code is not setting up rq->retries. This
patch also fixes up the sg_scsi_ioctl path.

Signed-off-by: Brian King <brking@us.ibm.com>
Signed-off-by: Jens Axboe <axboe@suse.de>