loci: fix OXM class and lengths

The class is now hardcoded to 0x8000 (OpenFlow Basic) instead of 0 (NXM).

The length of an OXM element does not include the header.
loci: allow dumping OF 1.3 objects
loci: fix version used to initialize wire match objects

We need to use the same version as the destination message, not the source
match.
type_maps: fix type value for of_match_v3