Stored num_losses even if all zeros [skip CI]
Stored num_losses even if all zeros [skip CI]


Former-commit-id: fc1f63d478a00a70da458d59712924ea8955b086 [formerly b9bd1f2b412d45b49b006ee25e85455283258a59]
Former-commit-id: 973181bc704ef5d498a8d690516fbf317f696692
gem/oq-engine,gem/oq-engine,gem/oq-engine,gem/oq-engine,gem/oq-engine