network: fix ability to use openvswitch with vlans

Use the correct enum constant when validating vlan usage.
This fixes a merge error in

  commit 6cb0ec48
  Author: Daniel P. Berrangé <berrange@redhat.com>
  Date:   Mon Sep 3 17:34:22 2018 +0100

    network: convert networkAllocateActualDevice to virNetworkPortDef
Reviewed-by: NMichal Privoznik <mprivozn@redhat.com>
Signed-off-by: NDaniel P. Berrangé <berrange@redhat.com>

src/network/bridge_driver.c

@@ -4814,7 +4814,7 @@ networkAllocatePort(virNetworkObjPtr obj,
         if (!(port->plugtype == VIR_NETWORK_PORT_PLUG_TYPE_HOSTDEV_PCI ||
               (port->plugtype == VIR_NETWORK_PORT_PLUG_TYPE_DIRECT &&
                port->plug.direct.mode == VIR_NETDEV_MACVLAN_MODE_PASSTHRU) ||
-              (port->plugtype == VIR_DOMAIN_NET_TYPE_BRIDGE &&
+              (port->plugtype == VIR_NETWORK_PORT_PLUG_TYPE_BRIDGE &&
                port->virtPortProfile &&
                port->virtPortProfile->virtPortType == VIR_NETDEV_VPORT_PROFILE_OPENVSWITCH))) {
             virReportError(VIR_ERR_CONFIG_UNSUPPORTED,