fix url to default cb
fix url to default cb

crossbario/autobahn-js,tavendo/AutobahnJS,oberstet/autobahn-js,tavendo/AutobahnJS,crossbario/autobahn-js,tavendo/AutobahnJS,crossbario/autobahn-js,oberstet/autobahn-js,oberstet/autobahn-js,oberstet/autobahn-js,crossbario/autobahn-js