Description of problem:
A restart of iscsi.service modifies records node.startup value from: 
node.startup = automatic
to: 
node.startup = onboot

This change hangs shutdown process since the session is never logged out.  

Version-Release number of selected component (if applicable):
Both:
iscsi-initiator-utils-6.2.0.874-7.el7.x86_64
iscsi-initiator-utils-6.2.0.874-10.el7.x86_64

How reproducible:
very

Steps to Reproduce:
1. Setup iSCSI initiator
2. log in to target for non-root device
3. systemctl restart iscsi.service

Actual results:

# grep -R "node.startup" /var/lib/iscsi/nodes/*
/var/lib/iscsi/nodes/<target>/<ip>/em1_iface0:node.startup = automatic
/var/lib/iscsi/nodes/<target>/<ip>/em1_iface1:node.startup = automatic

# systemctl restart iscsi.service

# grep -R "node.startup" /var/lib/iscsi/nodes/*
/var/lib/iscsi/nodes/<target>/<ip>/em1_iface0:node.startup = onboot
/var/lib/iscsi/nodes/<target>/<ip>/em1_iface1:node.startup = onboot

# reboot
Stuck at "Rebooting"

Expected results:

Manual restart of iscsi.service does not prevent shutdown/reboot

Additional info:

The iscsi.service calls script `iscsi-mark-root-nodes`: 
---
ExecStart=/usr/libexec/iscsi-mark-root-nodes (code=exited, status=0/SUCCESS)

This script does not perform any root dev verification and alters all node record: 

<snip>
while read t num p target flash; do
  # strip tag number from portal, keep "ip:port"
  portal=${p%,*}
  transport=${t%:}

  $ISCSIADM -m node -p $portal -T $target -o update -n node.startup -v onboot
</snip>

While is not ideal to restart iscsi.service, customer is performing this to reload altered iscsid.conf vs using `iscsiadm ... -o update` cli.