fix(library/init/option): remove unused variable
fix(library/init/option): remove unused variable

fpvandoorn/lean,leanprover/lean,Kha/lean,leanprover-community/lean,rlewis1988/lean,dselsam/lean,rlewis1988/lean,avigad/lean,fpvandoorn/lean,johoelzl/lean,Kha/lean,avigad/lean,leanprover-community/lean,rlewis1988/lean,leanprover-community/lean,fgdorais/lean,leodemoura/lean,johoelzl/lean,digama0/lean,digama0/lean,fgdorais/lean,dselsam/lean,dselsam/lean,fgdorais/lean,digama0/lean,Kha/lean,leanprover/lean,fpvandoorn/lean,johoelzl/lean,rlewis1988/lean,digama0/lean,leanprover-community/lean,avigad/lean,fgdorais/lean,digama0/lean,fpvandoorn/lean,avigad/lean,Kha/lean,fpvandoorn/lean,fpvandoorn/lean,leanprover/lean,fgdorais/lean,leodemoura/lean,Kha/lean,avigad/lean,leanprover-community/lean,leanprover/lean,dselsam/lean,Kha/lean,rlewis1988/lean,digama0/lean,leodemoura/lean,dselsam/lean,leodemoura/lean,leanprover-community/lean,johoelzl/lean,rlewis1988/lean,fgdorais/lean,leodemoura/lean,dselsam/lean,avigad/lean,johoelzl/lean,leanprover/lean,leodemoura/lean,leanprover/lean,johoelzl/lean