Removed a numpy warning in the GmfComputer [demos]
Removed a numpy warning in the GmfComputer [demos]


Former-commit-id: 5dab1d9e3027fc31891103de1a775ca1d0c45bbd [formerly 5fd06a47f7a43e8646c3649170fc3d5960fed8fd]
Former-commit-id: 41287388d4f8e9bd9475fd51d4a948c4c3e392c2
gem/oq-engine,gem/oq-engine,gem/oq-engine,gem/oq-engine,gem/oq-engine