Key() is pubkey: https://github.com/tendermint/tendermint/blob/master/p2p/peer.go#L212

but pex reactor uses IP: https://github.com/tendermint/tendermint/blob/master/p2p/pex_reactor.go#L267

This causes the pex to try dialing all the peers we're already connected to.

Either we change the Key() to be the address, or we store the PubKey in the address book too