[atlas] [Request] System tags for DNS resolution

On Sun, Nov 15, 2015 at 09:32:09AM +0200,
 Chris Amin <camin at ripe.net> wrote 
 a message of 64 lines which said:

> I think what is happening here is that all of those probes except
> for 17854 have at least *one* resolver which does respond to
> queries.

OK, I get it. I modified resolve-name
<https://github.com/RIPE-Atlas-Community/ripe-atlas-community-contrib/blob/master/resolve-name.py>
to continue if the fist resolver returns REFUSED or SERVFAIL
<https://github.com/RIPE-Atlas-Community/ripe-atlas-community-contrib/commit/d67a24f28db00cccca432731915b5811e16619c4>
Thanks for the explanations.

> why it has the tag "Doesn't Resolve A".

Do note that many tags documented in
<https://atlas.ripe.net/docs/probe-tags/#system-tags> do not work
(reported as [ripe.net #1195138]).

> I would be interested to hear your (or anybody else's) thoughts on
> whether you would use such a reliable/stable DNS resolution tag, and
> what kind of criteria you would expect for it to be applied.

The current system is not bad, once it is explained and the above bug
fixed.