Bump LXC package from 1.1.5 to 2.1.0. Version 2.x includes many
improvements and optimizations.

https://linuxcontainers.org/lxc/news/

Some tools like lxc-top are rewritten in C and are no longer broken and
dependent on lua.

Signed-off-by: Marko Ratkaj <marko.ratkaj@sartura.hr>

Signed-off-by: Marko Ratkaj <marko.ratkaj@sartura.hr>
Signed-off-by: Luka Perkov <luka@openwrt.org>

Signed-off-by: Luka Perkov <luka@openwrt.org>

Signed-off-by: Petar Koretic <petar.koretic@sartura.hr>