force_calculated not correctly updated when compute_ensemble is called

[mesonepigreco]

From discussion #187

After using the compute_ensemble with cluster. I can see the ensemble.force correctly store all the calculated results and therefore the ensemble.save_bin can save these results into .npy format. However, it seems the flag of ensemble.force_calculated is not set to be True so that the function ensemble.save does not save all the forces.

[mesonepigreco]

Probably, this is fixed in the last version, 1.4.1, by the commit mentioned.

[mesonepigreco]

Not, it has not.
The problem is that when the cluster is invoked in the calculation, the flags force_computed and stress_computed are not set when the configuration is compiled. Instead, this should have been fixed for the AiiDA ensemble and the generic ASE calculator. So, the problem occurs in the subroutine compute_cluster_batch of the Cluster.py file