Add reference to 'ansible-hardening' in Node Hardening section

[Luke Hinds]

Even though the section mentions 'The specifics on these steps are outside of the scope of this book', I believe the openstack/ansible-hardening project should be referenced, esp with it being an openstack project.

https://docs.openstack.org/security-guide/management/integrity-life-cycle.html#node-hardening

[Major Hayden (rackerhacker)]

I'll take this on!

[Luke Hinds (lhinds)]

good man, thx

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/482231

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/482231
Committed: https://git.openstack.org/cgit/openstack/security-doc/commit/?id=690d5924b70ef6441e6431b0a60f8ae844102317
Submitter: Jenkins
Branch: master

commit 690d5924b70ef6441e6431b0a60f8ae844102317
Author: Major Hayden <email address hidden>
Date: Mon Jul 10 12:57:47 2017 -0500

    Rework the 'node hardening' section

    This patch reworks the node hardening section to include some
    additional background and automated hardening options, including
    the ansible-hardening role. It also adds quite a few links to
    additional reading.

    The patch also improves the flow of the sections using RST's
    defintion syntax.

    Closes-Bug: 1703082
    Change-Id: I7ce40c9f452af9df12542903ffcd38adfd6ccb01