Update travis.yml to use/test requirements-py35-linux64.txt
Update travis.yml to use/test requirements-py35-linux64.txt


Former-commit-id: 5c122f4194703c447e2aea49c7d1396d6224660e [formerly 18602db95b4ea4d980ee2bff84a77c2d6a942be9]
Former-commit-id: e12313f64ee60da59df781e857b8eb5efda6ccd7
gem/oq-engine,gem/oq-engine,gem/oq-engine,gem/oq-engine,gem/oq-engine