Trigger policy-rc.d only if packages are installed

Change-Id: I1802b5de2a498b9874ab9d0c72cd103f43e42602
Closes-Bug: PROD-21129
diff --git a/neutron/server.sls b/neutron/server.sls
index 50bfba6..d012907 100644
--- a/neutron/server.sls
+++ b/neutron/server.sls
@@ -14,7 +14,7 @@
   - name: /usr/sbin/policy-rc.d
   - mode: 0775
   - contents: "exit 101"
-  - require_in:
+  - prereq:
     - pkg: neutron_server_packages
 
 policy_rcd_absent_ok: