Use standard get_urn_from_cert rather than obsolate extract_user_urn
Use standard get_urn_from_cert rather than obsolate extract_user_urn

MarshallBrinn/geni-ch,tcmitchell/geni-ch,MarshallBrinn/geni-ch,ahelsing/geni-ch,tcmitchell/geni-ch,ahelsing/geni-ch