defrag: fix reassembly with vlan

When creating a pseudo packet with the reassembled IP packet, the
parent's vlan id or id's are also needed. The defrag packet is run
through decode and the flow engine, where the vlan id is necessary
for connecting the packet to the correct flow.
vlan: support QinQ ethernet types

Add support for 802.1AD and 802.1QinQ in ethernet and vlan parsing.

Tickets: #814, #1103, #1104