wireguard: bump to 0.0.20181018

wireguard: bump to 0.0.20181018

ba2ab5d version: bump snapshot
5f59c76 tools: wg-quick: wait for interface to disappear on freebsd
ac7e7a3 tools: don't fail if a netlink interface dump is inconsistent
8432585 main: get rid of unloaded debug message
139e57c tools: compile on gnu99
d65817c tools: use libc's endianness macro if no compiler macro
f985de2 global: give if statements brackets and other cleanups
b3a5d8a main: change module description
296d505 device: use textual error labels always
8bde328 allowedips: swap endianness early on
a650d49 timers: avoid using control statements in macro
db4dd93 allowedips: remove control statement from macro by rewriting
780a597 global: more nits
06b1236 global: rename struct wireguard_ to struct wg_
205dd46 netlink: do not stuff index into nla type
2c6b57b qemu: kill after 20 minutes
6f2953d compat: look in Kbuild and Makefile since they differ based on arch
a93d7e4 create-patch: blacklist instead of whitelist
8d53657 global: prefix functions used in callbacks with wg_
123f85c compat: don't output for grep errors

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
(backported from 4653818dabe6d2f6e99b483ec256e4374dbb2c77)