wireguard: bump to 0.0.20180718

wireguard: bump to 0.0.20180718

80b41cd version: bump snapshot
fe5f0f6 recieve: disable NAPI busy polling
e863f40 device: destroy workqueue before freeing queue
81a2e7e wg-quick: allow link local default gateway
95951af receive: use gro call instead of plain call
d9501f1 receive: account for zero or negative budget
e80799b tools: only error on wg show if all interfaces failk

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
[Added commit log to commit description]
Signed-off-by: Kevin Darbyshire-Bryant <ldir@darbyshire-bryant.me.uk>