Remove unused import.
Remove unused import.


Former-commit-id: b19aabfa900e746e3c2180981b589f71bcbd76dd [formerly b19aabfa900e746e3c2180981b589f71bcbd76dd [formerly 95954e3368bb00985601d8cf5d2b205c7b637fbe]]
Former-commit-id: a40b589cbc1af70eda12bd9eb4bb0aaf07e4cc34
Former-commit-id: d83ec71d041d12f2d4a91ad0799423612a4101a9
gem/oq-engine,gem/oq-engine,gem/oq-engine,gem/oq-engine,gem/oq-engine