scsi: iscsi: Remove sessdestroylist

Just delete the sess from the session list instead of adding it to some
list we never use.

Link: https://lore.kernel.org/r/1593632868-6808-4-git-send-email-michael.christie@oracle.com


Signed-off-by: Mike Christie <michael.christie@oracle.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>