Memleak with 0.0.20171221-5 on Debian stretch

[Jason A. Donenfeld]

Hey Baptiste,

On Mon, Feb 12, 2018 at 8:42 AM, Baptiste Jonglez
<baptiste at bitsofnetworks.org> wrote:
> Actually, now that I talk about it, it's not 100% true: on this system,
> there is a second wireguard interface that is not currently used (it's
> provisionned to connect a future router that is not yet deployed).
>
> The interesting part: this interface has a single peer which has no
> endpoint but a persistent keepalive.

That's a super useful observation! I'm guessing this will fix it:
https://git.zx2c4.com/WireGuard/commit/?id=c5c22fb9bad1807a612b6055e0049d68f4600605

I'm still analyzing everything to find other places where I might have
missed something, but hopefully the above does it.

Jason