[oe] [meta-openembedded] Wireguard broken with 5.1+ kernels

[Scott Ellis]

This kernel commit removes nf_nat_core.h which breaks wireguard 20190123.

    commit d2c5c103b1337f590b7edf1509a6e294bdf22402
    Author: Florian Westphal <fw at strlen.de>
    Date:   Tue Feb 19 17:38:27 2019 +0100

        netfilter: nat: remove nf_nat_l3proto.h and nf_nat_core.h


Version 20190406 of wireguard fixes this.

Will a patch to upgrade the wireguard version on the warrior branch be
accepted?