As far as any of us can work out, question/format/qti_two does not work, and there is no prospect of anyone fixing it, so it has bene removed Moodle 2.2. That is tracked as MDL-29921.
If we are wrong about that, please shout now.
QTI2 would still be a worthwhile feature to have in Moodle, if anyone is able to work on it, but we could not see any value in the existing, broken code, which is why we are removing it. The old code will, of course, sill be available in Moodle 2.1 downloads, and in git history.