iscsi-target: Fix iscsit_sequence_cmd reject handling for iser

commit 561bf158 upstream

This patch moves ISCSI_OP_REJECT failures into iscsit_sequence_cmd()
in order to avoid external iscsit_reject_cmd() reject usage for all
PDU types.

It also updates PDU specific handlers for traditional iscsi-target
code to not reset the session after posting a ISCSI_OP_REJECT during
setup.

(v2: Fix CMDSN_LOWER_THAN_EXP for ISCSI_OP_SCSI to call
     target_put_sess_cmd() after iscsit_sequence_cmd() failure)

Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
Cc: Or Gerlitz <ogerlitz@mellanox.com>
Cc: Mike Christie <michaelc@cs.wisc.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>