PropagationGuidedNeighborhood computes the wrong value of logSum

It looks like someone forgot to delete lines 106 to 108 in [PropagationGuidedNeighborhood.java](https://github.com/chocoteam/choco-solver/blob/ab04ff513e8c278916105baa4ab4334dd4d22c8a/src/main/java/org/chocosolver/solver/search/loop/lns/neighbors/PropagationGuidedNeighborhood.java#L106).

In previous versions, line 105 was `logSum = 0` but was at some point this updated to be `logSum = Arrays.stream(variables).mapToDouble(v -> Math.log(v.getDomainSize())).sum();`, which directly computes the logSum and makes lines 106 to 108 obsolete.
However, because lines 106 to 108 remain and increase the value of logSum, the resulting value is actually two times the intended value.