Fix permissions of ContrailPlugin.ini

ContrailPlugin.ini potentially contains password and is world readable.
To fix this we need set user/group to neutron and permissions to 640.

Change-Id: I97a1faff75e5db292f334a713f9b064f3a6c171b
Related-Prod: PROD-25326 (PROD:25326)
diff --git a/neutron/server.sls b/neutron/server.sls
index 25b7d3c..e13dc75 100644
--- a/neutron/server.sls
+++ b/neutron/server.sls
@@ -45,6 +45,9 @@
   file.managed:
   - source: salt://neutron/files/{{ server.version }}/ContrailPlugin.ini
   - template: jinja
+  - user: neutron
+  - group: neutron
+  - mode: 640
   - require:
     - pkg: neutron_server_packages
     - pkg: neutron_contrail_package