Pass neutron_service_region to service_setup tasks

This was missing so the default RegionOne would always be used.

Depends-On: https://review.opendev.org/697845/
Change-Id: I92ec3e512600dc80398c55ed37ff2b6c7ca7c23f

tasks/main.yml

@@ -185,6 +185,7 @@
     _service_setup_host: "{{ neutron_service_setup_host }}"
     _service_setup_host_python_interpreter: "{{ neutron_service_setup_host_python_interpreter }}"
     _service_project_name: "{{ neutron_service_project_name }}"
+    _service_region: "{{ neutron_service_region }}"
     _service_users:
       - name: "{{ neutron_service_user_name }}"
         password: "{{ neutron_service_password }}"