clear() does not detach ioctl handlers

[benzea]

OK, not sure about this one, so opening a bug.

Should clear implicitly detach all ioctl handlers, or should people still need to detach them explicitly?

Note that there is an internal hash table, to allow detaching. And this hash table might get autodated with clear() as the device is not removed there. But then, what happens if the socket/device is removed from the disk in some other way?