The systemd-sysctl service includes condition that /proc/sys/ has to be read-write.
In lxc only /proc/sys/net/ is read-write which causes the condition to fail and service not to run.
This patch changes the check to /proc/sys/net/ and makes the service apply only rules that are in net tree.
Signed-off-by: Jakub Sztandera <kubuxu@gmail.com>