scsi: qla2xxx: edif: Fix stall session after app start

For N2N, qla2x00_wait_for_sess_deletion call flushes
a session which accidentally clear the scan_flag and thus prevents
re-login to occur and causes session to stall.

Use session delete to avoid the accidental clearing of scan_flag.

Signed-off-by: Quinn Tran <qutran@marvell.com>
Signed-off-by: Nilesh Javali <njavali@marvell.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>