fix tank-postloader: log was created before args parsing
fix tank-postloader: log was created before args parsing

nettorta/yandex-tank,yandex/yandex-tank,fomars/yandex-tank,netortik/yandex-tank,fomars/yandex-tank,netortik/yandex-tank,yandex/yandex-tank,f2nd/yandex-tank,f2nd/yandex-tank,nettorta/yandex-tank