regionOne is hardcoded only as default:
[root@undercloud-0 openstack-tripleo-heat-templates]# grep -R regionOne
puppet/services/aodh-base.yaml: default: 'regionOne'
Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.
For information on the advisory, and where to find the updated
files, follow the link below.
If the solution does not work for you, open a new bug report.