decnet: netdevice refcount leak

While working on device refcount stuff, I found a device refcount leak
through DECNET.
This nasty bug can be used to hold refcounts on any !DECNET netdevice.
Signed-off-by: NEric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/decnet/sysctl_net_decnet.c

@@ -263,11 +263,10 @@ static int dn_def_dev_strategy(ctl_table *table,
 			return -ENODEV;
 
 		rv = -ENODEV;
-		if (dev->dn_ptr != NULL) {
+		if (dev->dn_ptr != NULL)
 			rv = dn_dev_set_default(dev, 1);
-			if (rv)
-				dev_put(dev);
-		}
+		if (rv)
+			dev_put(dev);
 	}
 
 	return rv;