fix for situations where the term added is None, in which case, it's term type is 'L'
fix for situations where the term added is None, in which case, it's term type is 'L'

git-svn-id: 60eb48102d1ca0c284ab3654bef916b01e1b221b@666 4f84a9ca-5c3e-0410-8a68-0bdf370325d5

nwebs/rdflib