Fixed a numpy warning
Fixed a numpy warning


Former-commit-id: ef23c3ecf01452a2e60aad5d717e8c1a09ed258f [formerly ca6c5a72619a0fcc3884f32b2d061811b912ae98]
Former-commit-id: 6863d5450164a4e1a8da757d98f9bd43f712e7c7
gem/oq-engine,gem/oq-engine,gem/oq-engine,gem/oq-engine,gem/oq-engine