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.

src/decode.c

@@ -331,6 +331,9 @@ Packet *PacketDefragPktSetup(Packet *parent, uint8_t *pkt, uint16_t len, uint8_t
     p->datalink = DLT_RAW;
     /* tell new packet it's part of a tunnel */
     SET_TUNNEL_PKT(p);
+    p->vlan_id[0] = parent->vlan_id[0];
+    p->vlan_id[1] = parent->vlan_id[1];
+    p->vlan_idx = parent->vlan_idx;
 
     SCReturnPtr(p, "Packet");
 }