Comment 8 for bug 1755602

Thanks for the input.

I think what I meant was, the operator has to know "if I have Ironic, I have to use --by-service, else plain discover_hosts is fine." And if we're going to add a "mapped" bit to the Service object going forward anyway to make --by-service efficient, why not just keep the one efficient way of doing it and not give operators an option where they have to know "if I have Ironic, I should use --by-service" and keep the two different efficient code paths instead of dropping one and keeping one efficient code path. (Again, this is all regarding the forward-looking solution, not the backportable solution we're doing as a first step.)