Don't create the job record if it already exists, as in the case of an oq-server calculation
Don't create the job record if it already exists, as in the case of an oq-server calculation


Former-commit-id: cb4d296716c7ab786edd0ec68b794be0616fc859
gem/oq-engine,gem/oq-engine,gem/oq-engine,gem/oq-engine,gem/oq-engine