[Cake] Correct 'change' behaviour

[Jonathan Morton]

> On 3 Nov, 2015, at 15:14, Toke Høiland-Jørgensen <toke at toke.dk> wrote:
> 
> Kevin Darbyshire-Bryant <kevin at darbyshire-bryant.me.uk> writes:
> 
>> Interestingly I think the opposite. On a change parameters should be
>> left alone unless they're the thing I'm changing. It's a 'change' to
>> an instantiation, *not* an instantiation if you get my drift.
> 
> Yes, that is indeed implied in the 'change' verb. However, the tc verb
> is 'replace'. If we go with the "leave things alone" paradigm, there
> will need to be some way to explicitly specify defaults…

But tc has both “change” and “replace” verbs.  They should do different things; the latter implies removing an existing qdisc and inserting a new one.

 - Jonathan Morton