Fix Blazar Nova aggregate in multi-region setup

The Nova aggregate was always defaulting to some region (usually first
in the Keystone endpoint list) when registering the Nova aggregate for
Blazar. Add in a region override to ensure we are always writing to the
region being deployed.

Change-Id: I3f921ac51acab1b1020a459c07c755af7023e026

ansible/roles/blazar/tasks/bootstrap.yml

@@ -41,6 +41,7 @@
     --os-username admin
     --os-password {{ keystone_admin_password }}
     --os-user-domain-name default
+    --os-region-name {{ openstack_region_name }}
     aggregate create {{ blazar_aggregate_pool_name }}
   register: blazar_host_aggregate
   changed_when: blazar_host_aggregate is success