removed unused import
removed unused import


Former-commit-id: 6218f522fe4c5a2ccdf9cdf6dae25370924b887e [formerly 6218f522fe4c5a2ccdf9cdf6dae25370924b887e [formerly 52c6939726d82974b02cbc6387cf79001cef5e17]]
Former-commit-id: a8cce235f75119f370ee1ab495c33278f041ed19
Former-commit-id: a9a3aa336b1aa0942a0cb3bc1ec1e00689cc5b08
gem/oq-engine,gem/oq-engine,gem/oq-engine,gem/oq-engine,gem/oq-engine