fix handling of trivial curves
fix handling of trivial curves


Former-commit-id: 41213ee49da1a033de3e14634288585922d1c25b [formerly 92e0561938873e8ac1641351b4480c6372315e21] [formerly 92e0561938873e8ac1641351b4480c6372315e21 [formerly 72736c3a39a1cf5fe70f15eaeaace7910cb57172]]
Former-commit-id: 0e6d33889e1923f190d9e3a061bae732e1f154ff
Former-commit-id: 3cada3f763c2a13376ada83efc79d0a5658806fd
gem/oq-engine,gem/oq-engine,gem/oq-engine,gem/oq-engine,gem/oq-engine