systemd: fix lxc-containers vs lxc-net ordering (v3)

Per pitti's suggestion, use After= to force lxc to wait for lxc-net to finish
running.

Signed-off-by: Serge Hallyn <serge.hallyn@ubuntu.com>
Reviewed-By: Martin Pitt <martin.pitt@ubuntu.com>

config/init/systemd/lxc.service.in

@@ -1,6 +1,6 @@
 [Unit]
 Description=LXC Container Initialization and Autoboot Code
-After=syslog.target network.target
+After=syslog.target network.target lxc-net.service
 Wants=lxc-net.service
 
 [Service]