net: use synchronize_net() in dev_change_name()

dev_change_name() holds RTNL, we better use synchronize_net()
instead of plain synchronize_rcu().
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/core/dev.c

@@ -1239,7 +1239,7 @@ int dev_change_name(struct net_device *dev, const char *newname)
 	netdev_name_node_del(dev->name_node);
 	write_unlock(&dev_base_lock);
 
-	synchronize_rcu();
+	synchronize_net();
 
 	write_lock(&dev_base_lock);
 	netdev_name_node_add(net, dev->name_node);