added meta for JobStats model
added meta for JobStats model


Former-commit-id: 8599f99b45ac98f40dbc7493fa664c63f5af9101 [formerly 253394d6141ebb98d50bec3e843233a659a40d6e]
Former-commit-id: 05a811e35eeb35c11aa8d9dae614fb6c7521454e
gem/oq-engine,gem/oq-engine,gem/oq-engine,gem/oq-engine,gem/oq-engine