Comment 52 for bug 1573272

Attached v2 patches for artful and SRU releases; instead of changing the vlan if-pre-up.d script to use only ifup instead of ip link up, change the script to use both; first try ifup for the vlan raw device, then if that fails (e.g. because ifupdown has no configuration for the vlan raw device) try directly bringing up the vlan raw device using the previous way, i.e. ip link set DEV up.