Add upstream OpenWrt
OpenWrt should be already in linuxcontainers. This could help us more easily test OpenWrt-specific features for packaging.
Linux containers have basic support for OpenWrt images. However, architecture is right now limited only to amd64 (https://images.linuxcontainers.org/)
It could be probably added by extending Jenkins jobs definition available here https://github.com/lxc/lxc-ci
Edit: Upstream issue https://github.com/lxc/lxc-ci/issues/269