wireguard: bump to version 0.0.20171111

wireguard: bump to version 0.0.20171111

Contains a number of important fixes. From the relase notes:

https://lists.zx2c4.com/pipermail/wireguard/2017-November/001935.html

  * netlink: plug memory leak
  * qemu: check for memory leaks

  There was a small memory leak on the netlink configuration layer that's now
  been fixed.

  * netlink: make sure we reserve space for NLMSG_DONE

  A rather important change - due to an upstream kernel bug, that's existed
  since the advent of netlink itself, sometimes wg(8) failed to receive valid
  data back from kernelspace, resulting in "ENOBUFS" when trying to dump all
  peers. This patch works around it while we wait for upstream to commit the
  fix.

Signed-off-by: Peter Korsgaard <peter@korsgaard.com>