ironic-lib 2.16.4 release

meta:version: 2.16.4
meta:diff-start: -
meta:series: stein
meta:release-type: release
meta:pypi: yes
meta:first: no
meta:release:Author: Mark Goddard <mark@stackhpc.com>
meta:release:Commit: Mark Goddard <mark@stackhpc.com>
meta:release:Change-Id: I6d9bf2c38519d69ac0798769af78e3178f10725f
meta:release:Code-Review+1: Hervé Beraud <hberaud@redhat.com>
meta:release:Code-Review+2: Sean McGinnis <sean.mcginnis@gmail.com>
meta:release:Code-Review+2: Thierry Carrez <thierry@openstack.org>
meta:release:Workflow+1: Thierry Carrez <thierry@openstack.org>