When a Direct3D 9Ex device fails to reset, it gets put into the lost
state, so set the lost_device flag and don't attempt to present until
the device moves out of that state. Failure to recreate the size-
dependent objects should set lost_device as well, since we shouldn't try
to present in that state.
Also, it looks like I was too eager to remove code that sets priv
members to NULL and I accidentally removed some that was needed.