Also pass FWAAS conf to VPN agent if enabled

If q-vpn is enabled, the Neutron neutron-vpn-agent is started
instead of the neutron-l3-agent, but only neutron-l3-agent receives
the fwaas_driver config when q-fwaas is enabled.  This ensures the FW driver
config is passed to either so that a properly configured agent is running
when the FWAAS extensions are enabled.

Closes-bug: #1310858

Change-Id: I237d2831a6b87ae46dfef047d3dc0b85fa6423d3
diff --git a/lib/neutron b/lib/neutron
index 726f676..9e1e787 100644
--- a/lib/neutron
+++ b/lib/neutron
@@ -497,6 +497,7 @@
 
     if is_service_enabled q-fwaas; then
         L3_CONF_FILES="$L3_CONF_FILES --config-file $Q_FWAAS_CONF_FILE"
+        VPN_CONF_FILES="$VPN_CONF_FILES --config-file $Q_FWAAS_CONF_FILE"
     fi
     if is_service_enabled q-vpn; then
         screen_it q-vpn "cd $NEUTRON_DIR && $AGENT_VPN_BINARY $VPN_CONF_FILES"