Strange behavior when a peer has the same key as the interface

[Vojtěch Káně]

> This is by design across all implementations, so that multiple peers can share the same stanzas after the [Interface] section.
Does that mean it's unfixable in the meaning you cannot detect it and 
return appropriate error?


While being clearly my mistake, it took me multiple hours to understand 
the problem instead of simply getting `cannot set peer foo as it already 
is a public key of interface bar`.