removed some unused imports
removed some unused imports


Former-commit-id: d7b518d0da3dd311e040d6d2874278cfebbb4982 [formerly 02369fd3c2ec322b0bf38e7b67516397e8d70ec7]
Former-commit-id: b634caec6b7ed5820d1f1bcc2b59d9f98f43ed7b
gem/oq-engine,gem/oq-engine,gem/oq-engine,gem/oq-engine,gem/oq-engine