RDF parser omits ID of extracted licensing info

[armintaenzertng]

Parsing an RDF document like the SPDXRdfExample-v2.2.spdx.rdf.xml results in extracted licensing infos such as this:

ExtractedLicensingInfo(license_id=None, extracted_text='"THE BEER-WARE LICENSE" (Revision 42):\nphk@FreeBSD.ORG wrote this file. As long as you retain this notice you\ncan do whatever you want with this stuff. If we meet some day, and you think this stuff is worth it, you can buy me a beer in return Poul-Henning Kamp', license_name='Beer-Ware License (Version 42)', cross_references=['http://people.freebsd.org/~phk/'], comment='The beerware license has a couple of other standard variants.')

That is, license_id=None while it should be license_id="LicenseRef-Beerware-4.2"