false positives on UPnP plugin

[Dmitriy Kropivnitskiy]

I have tested several netowrks with 1.1.12 and upnp plugin
seems to give positives even on *nix systems that couldn't possibly 
run UPnP ( I believe that is XP specific feature ). What's wrong?
I looked at the nasl code and it seems fine ( except that strange place 
where it expects to recieve SYN as response to RSET )