[dnsdist] Add ECS to response

[Casey Deccio]

> On Jul 4, 2019, at 6:19 AM, Arsen STASIC <arsen.stasic at univie.ac.at> wrote:
> 
> Hi Casey,
> 
> * Casey Deccio <casey at deccio.net> [2019-07-04 01:55 (-0600)]:
>> 
>> Oh, I suppose it all depends on what you're trying to accomplish :). I think I've found another way to accomplish what I needed.  Thanks!
> 
> Are you willing to share your another ways with us?

Sure.  But I should mention that 1) of course I need to get it working first and 2) my objectives have evolved a bit :)

Casey