Revert previous patches due to bug

We have a bug (possibly because of returning draw from
root move list), it is possible to see when looking at
games with a GUI, we can see rarely but consistently the
score return as #0 for many depths until it comes back to
normal values.

Revert patches until it is not fixed.

Signed-off-by: Marco Costalba <mcostalba@gmail.com>