detail listener is broken in the 3.2.9 release

[Bjørn Mork]

I bisected it down to
https://github.com/FreeRADIUS/freeradius-server/commit/5691cbc615e515490fc490965baff58236d64cd3

It didn't revert cleanly so I looked a bit closer and noticed that it
ends up changing

 if (!request->packet->vps) {
 ..
 } else {
  rcode = 0;
 }
 ..
 return 1;

into a more direct

 if (request->packet->vps) return 0;


The problem is obviously that the return value changes from 1 to 0.
Simple fix ready for pulling at
https://github.com/FreeRADIUS/freeradius-server/pull/5870


(yes, I found this and verified the fix in a real world installation)


Bjørn