Sorry I missed it.

BTW, we have two plan to solve it:

1. command/fluentd.rb have `opts = Fluent::Supervisor::DEFAULT_OPTIONS` as an initial value, not `opts = { }`. Then `DEFAULT_OPTIONS.merge(opt)` won't be needed.
2. Replace `DEFAULT_OPTIONS.merge(opt)` with the right way. It will care array correctly.

I think plan 1 is better because its simple solution for this PR purpose. I'll do it.