Fix lint error about unused import.
Fix lint error about unused import.

dribnet/fuel,vdumoulin/fuel,dmitriy-serdyuk/fuel,capybaralet/fuel,udibr/fuel,markusnagel/fuel,vdumoulin/fuel,janchorowski/fuel,aalmah/fuel,aalmah/fuel,dribnet/fuel,udibr/fuel,markusnagel/fuel,mila-udem/fuel,capybaralet/fuel,mila-udem/fuel,dmitriy-serdyuk/fuel,janchorowski/fuel