[NETNS]: Memory leak on network namespace stop.

Network namespace allocates 2 kernel netlink sockets, fibnl &
rtnl. These sockets should be disposed properly, i.e. by
sock_release. Plain sock_put is not enough.
Signed-off-by: Denis V. Lunev <den@openvz.org>
Tested-by: Alexey Dobriyan <adobriyan@openvz.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/core/rtnetlink.c

@@ -1384,7 +1384,7 @@ static void rtnetlink_net_exit(struct net *net)
 		 * free.
 		 */
 		sk->sk_net = get_net(&init_net);
-		sock_put(sk);
+		sock_release(net->rtnl->sk_socket);
 		net->rtnl = NULL;
 	}
 }

net/ipv4/fib_frontend.c

@@ -881,7 +881,7 @@ static void nl_fib_lookup_exit(struct net *net)
 	 * initial network namespace. So the socket will  be safe to free.
 	 */
 	net->ipv4.fibnl->sk_net = get_net(&init_net);
-	sock_put(net->ipv4.fibnl);
+	sock_release(net->ipv4.fibnl->sk_socket);
 }
 
 static void fib_disable_ip(struct net_device *dev, int force)