sockets: Make sure sun_family is at the right offset
sockets: Make sure sun_family is at the right offset

LWIP puts some extra fields before the family, so ensure that
sockaddr_un::sun_family is in the same place as sa_family.

bowlofstew/sv6,aclements/sv6,aclements/sv6,aclements/sv6,bowlofstew/sv6,aclements/sv6,bowlofstew/sv6,aclements/sv6,bowlofstew/sv6,bowlofstew/sv6