[bgpvpn] Install plugin before database sync

Change-Id: I007cd5061d63e1be7d805a8176549601274013aa
diff --git a/neutron/server.sls b/neutron/server.sls
index e8782d0..5a410f8 100644
--- a/neutron/server.sls
+++ b/neutron/server.sls
@@ -346,6 +346,8 @@
 bgpvpn_packages:
   pkg.installed:
   - names: {{ server.pkgs_bgpvpn }}
+  - require_in:
+    - sls: neutron.db.offline_sync
 
 {% if server.bgp_vpn.driver == "bagpipe" %}