[bug] No keep-alives sent when private is set via PostUp

[Jason A. Donenfeld]

Hi Maxim,

Thanks for the bug report! I think indeed you're right about this. Can
you test if this commit fixes the issue for you?

https://git.zx2c4.com/wireguard-linux/commit/?id=3ac1bf099766f1e9735883d5127148054cd5b30a

It at least satisfies the test case I added.

Until this patch hits stable kernels, you can probably work around
this by changing your PostUp into a PreUp. I adjusted the man page
here:

https://git.zx2c4.com/wireguard-tools/commit/?id=9d42bd1ab9d707f7a72162d36c9b37cc9bdf480e

Jason