lib/upnp: Correct the result deduplication mechanism (fixes #3578)
lib/upnp: Correct the result deduplication mechanism (fixes #3578)

GitHub-Pull-Request: https://github.com/syncthing/syncthing/pull/3618

uok/syncthing,le9i0nx/syncthing,kluppy/syncthing,kamadak/syncthing,Kudalufi/syncthing,wweich/syncthing,cherylquirion/syncthing,ProactiveServices/syncthing,brgmnn/syncthing,imsodin/syncthing,rumpelsepp/syncthing,AudriusButkevicius/syncthing,AudriusButkevicius/syncthing,syncthing/syncthing,lkwg82/syncthing,syncthing/syncthing,wweich/syncthing,syncthing/syncthing,plouj/syncthing,plouj/syncthing,xduugu/syncthing,jryans/syncthing,lkwg82/syncthing,AudriusButkevicius/syncthing,imsodin/syncthing,rumpelsepp/syncthing,le9i0nx/syncthing,imsodin/syncthing,kamadak/syncthing,Kudalufi/syncthing,nrm21/syncthing,kamadak/syncthing,ProactiveServices/syncthing,xduugu/syncthing,ProactiveServices/syncthing,plouj/syncthing,AudriusButkevicius/syncthing,imsodin/syncthing,lkwg82/syncthing,uok/syncthing,ProactiveServices/syncthing,syncthing/syncthing,nrm21/syncthing,kluppy/syncthing,syncthing/syncthing,nrm21/syncthing,jryans/syncthing,kamadak/syncthing,xduugu/syncthing,uok/syncthing,jryans/syncthing,plouj/syncthing,kluppy/syncthing,uok/syncthing,imsodin/syncthing,nrm21/syncthing,kluppy/syncthing,lkwg82/syncthing,brgmnn/syncthing,le9i0nx/syncthing,brgmnn/syncthing,cherylquirion/syncthing,rumpelsepp/syncthing,wweich/syncthing,wweich/syncthing,cherylquirion/syncthing,le9i0nx/syncthing,Kudalufi/syncthing,rumpelsepp/syncthing,syncthing/syncthing,xduugu/syncthing,jryans/syncthing,brgmnn/syncthing,Kudalufi/syncthing,cherylquirion/syncthing