neutron: fix neutron-server config.json with VMware

Missing comma in config.json template rendered invalid JSON with VMware
plugin agent.

Closes-Bug: #1939080

Change-Id: I3d0c6421e3da7e1e753b99cf87c32fc238a21523

ansible/roles/neutron/templates/neutron-server.json.j2

@@ -26,7 +26,7 @@
             "owner": "neutron",
             "optional": {{ (neutron_plugin_agent not in ['vmware_nsxv', 'vmware_nsxv3', 'vmware_dvs']) | string | lower }},
             "perm": "0600"
-        }{% endif %}
+        },{% endif %}
 {% if check_extra_ml2_plugins is defined and check_extra_ml2_plugins.matched > 0 %}{% for plugin in check_extra_ml2_plugins.files %}
         {
             "source": "{{ container_config_directory }}/{{ plugin.path | basename }}",

releasenotes/notes/fix-neutron-vmware-4a8804399d47d8d7.yaml

+---
+fixes:
+  - |
+    Fixes an issue with ``config.json`` for ``neutron-server`` when a VMware
+    plugin agent is used.