bridge: netfilter: fix a memory leak

nf_bridge_alloc() always reset the skb->nf_bridge, so we should always
put the old one.
Signed-off-by: NChangli Gao <xiaosuo@gmail.com>
Signed-off-by: NBart De Schuymer <bdschuym@pandora.be>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/bridge/br_netfilter.c

@@ -162,8 +162,8 @@ static inline struct nf_bridge_info *nf_bridge_unshare(struct sk_buff *skb)
 		if (tmp) {
 			memcpy(tmp, nf_bridge, sizeof(struct nf_bridge_info));
 			atomic_set(&tmp->use, 1);
-			nf_bridge_put(nf_bridge);
 		}
+		nf_bridge_put(nf_bridge);
 		nf_bridge = tmp;
 	}
 	return nf_bridge;