Permit null mac address column values
Permit null mac address column values

Makes mac addresses behavior consisten with IPV4 columns
We've had nullable mac addresses in the schema for a while,
it makes sense to have the semantics of the column types be
the same.

guillaume-philippon/aquilon,guillaume-philippon/aquilon,quattor/aquilon,stdweird/aquilon,quattor/aquilon,stdweird/aquilon,quattor/aquilon,guillaume-philippon/aquilon,stdweird/aquilon