oslo.service 2.3.1 release

meta:version: 2.3.1
meta:diff-start: -
meta:series: victoria
meta:release-type: release
meta:pypi: yes
meta:first: no
meta:release:Author: Hervé Beraud <hberaud@redhat.com>
meta:release:Commit: Hervé Beraud <hberaud@redhat.com>
meta:release:Change-Id: I07de3a77e473859e81fe3bedc79d0ac6904dde2b
meta:release:Code-Review+1: Ben Nemec <openstack@nemebean.com>
meta:release:Code-Review+2: Thierry Carrez <thierry@openstack.org>
meta:release:Workflow+1: Thierry Carrez <thierry@openstack.org>