Terry Wilson researched the option to backport this feature and mentioned it requires a DB migration in addition to code conflicts -

" Even just the main patch has lots of conflicts, including some db migration stuff, would probably be pretty messy

Unmerged paths:
  (use "git add/rm <file>..." as appropriate to mark resolution)

	deleted by us:   neutron/agent/linux/iptables_comments.py
	both modified:   neutron/agent/linux/iptables_firewall.py
	both modified:   neutron/db/migration/alembic_migrations/versions/HEAD
	both modified:   neutron/db/portsecurity_db.py
	both modified:   neutron/plugins/ml2/plugin.py
	deleted by us:   neutron/tests/functional/agent/linux/test_iptables_firewall.py
	both modified:   neutron/tests/unit/test_iptables_firewall.py
	both modified:   setup.cfg

"

Because of the complications mentioned in comment #2 we do not have concrete plans to backport this feature to OSP6.