Use valid_interfaces instead of os_interface for placement

The [placement].os_interface option was replaced by
[placement].valid_interfaces in Queens and was removed in Rocky.

Change-Id: I306c57305b9088159dd18af4aa373bbc39a8b881
Closes-Bug: #1853621

ansible/roles/nova-cell/templates/nova.conf.j2

@@ -197,7 +197,7 @@ user_domain_name = {{ default_user_domain_name }}
 project_name = service
 project_domain_name = {{ default_project_domain_name }}
 region_name = {{ openstack_region_name }}
-os_interface = internal
+valid_interfaces = internal
 
 [notifications]
 {% if enable_ceilometer | bool or enable_searchlight | bool or enable_designate | bool or enable_neutron_infoblox_ipam_agent | bool %}

ansible/roles/nova/templates/nova.conf.j2

@@ -169,7 +169,7 @@ user_domain_name = {{ default_user_domain_name }}
 project_name = service
 project_domain_name = {{ default_project_domain_name }}
 region_name = {{ openstack_region_name }}
-os_interface = internal
+valid_interfaces = internal
 
 [notifications]
 {% if enable_ceilometer | bool or enable_searchlight | bool or enable_designate | bool or enable_neutron_infoblox_ipam_agent | bool %}