Plugin ser/des logic does not match model

There is no such thing as "There is no Prefix" (equivalent to the OpenFlow hasMask()) for an Ipv4 or Ipv6 Prefix.

In order to be a prefix it always has a /X even if that is 128 for v6 or /32 for v4.

As long as we express Matches as Prefixes in the data model all ser/des has to normalize to hasMask() form in order to ensure that data passed from northbound matches what comes from southbound.

So we either change the model to use something different from Prefix or we make the code match the model (presently it does not).