Make sure that of_core match dl_vlan can match these combinations: untagged, value/mask

[viniarck]

Make sure that of_core match dl_vlan can match these combinations: untagged, value/mask

To cross reference this comment, specifically the point number 4, let's also install the following kind of flows on OvS and later on NoviFlow, just so we can compare how they end up installed in the control-plane and fix any inconsistencies on of_core:

1. Install a flow matching dl_vlan untagged and generate traffic
2. Install a flow matching dl_vlan exact vlan with all 1s, vlan 3 for instance -> 3/0xfff
3. Install a flow matching dl_vlan adjacent vlans like 3-4 ->3/0xffe
4. Confirm that the concept of dl_vlan any (Allow creation of EVCs for untagged UNI - support matching packets without a VLAN tag mef_eline#219) in theory is equivalent to a number/0