[PATCH wireguard-go] tun: avoid leaking sock fd in CreateTUN error cases

[Tobias Klauser]

On 2021-09-23 at 17:54:20 +0200, Jason A. Donenfeld <Jason at zx2c4.com> wrote:
> Applied, thanks! I'm curious: is this a bug you ran into somewhere?

I've not seen this causing problems with wireguard-go specifically, but
have seen issues with leaked fds elsewhere. So by now I'm attentive of
the pattern and send fixes where I notice it :)