Currently, mef_eline takes the instantiates new instances of Link in order to reserve vlans for its paths. This somewhat makes sense in the case of using the link metadata to track which vlans a particular path is using. However, it doesn't make sense for keeping track of the vlan allocations on the link itself. Currently, links allocate vlans, by allocating them from the interfaces. However, if this changes as is being proposed in kytos-ng/kytos#554, then this would no longer be the case. This will require decoupling the existing Path model from Link.