oslo.messaging 10.2.1 release

meta:version: 10.2.1
meta:diff-start: -
meta:series: train
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: Ie4f1057048bfdc55c1c403654da8831461199468
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>