added utils.tasks.oq_task() decorator
added utils.tasks.oq_task() decorator


Former-commit-id: d951b340b0951ddb8aaf26149d1ac827f27f7834 [formerly 2895f0e1f33d6850675635e3e0abaed4fb875712]
Former-commit-id: 1c611656efe23325ff29d1c22c3b3ba89ec38156
gem/oq-engine,gem/oq-engine,gem/oq-engine,gem/oq-engine,gem/oq-engine