Do not attempt to dial loopback address

[binarybaron]

We shouldn't even attempt to dial a loopback address (e.g 127.0.0.1) because this cannot be successfull. We should do something along the line of:

https://github.com/UnstoppableSwap/core/blob/d0108fd857c559ea7b2667c05598a55e45cb63a4/swap/src/network/tor_transport.rs#L159-L166

[umgefahren]

I agree but this problem is more complicated than it seems. For just the loopback address it's true but this should then also be implemented for local addresses and that's pretty hard to determine.
However, if you are interested, I made a PR to rust to detect those special cases for IPv6 too: rust-lang/rust#129238
I would suggest waiting until that is merged before we go forward.