Unknown options get an encapsulated space in unpackOptions4

I have a concern about this code applied by LibDHCP::unpackOptions4 to create an option with no definition:

        } else if (num_defs == 0) {
            opt = OptionPtr(new Option(Option::V4, opt_type,
                                       buf.begin() + offset,
                                       buf.begin() + offset + opt_len));
            opt->setEncapsulatedSpace(DHCP4_OPTION_SPACE);
        } else {

Even I believe the encapsulated space is never used I think it should not be set (as the v6 code does).