scsi: scsi_dh_alua: always use a 2 second delay before retrying RTPG

Retrying immediately after we've received a 'transitioning' sense code is
pretty much pointless, we should always use a delay before retrying.  So
ensure the default delay is applied before retrying.

Signed-off-by: Hannes Reinecke <hare@suse.com>
Tested-by: Zhangguanghui <zhang.guanghui@h3c.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>