net: Kill hold_net release_net

hold_net and release_net were an idea that turned out to be useless.
The code has been disabled since 2008.  Kill the code it is long past due.

Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv6/addrlabel.c b/net/ipv6/addrlabel.c
index e43e79d..59c7930 100644
--- a/net/ipv6/addrlabel.c
+++ b/net/ipv6/addrlabel.c
@@ -129,9 +129,6 @@
 /* Object management */
 static inline void ip6addrlbl_free(struct ip6addrlbl_entry *p)
 {
-#ifdef CONFIG_NET_NS
-	release_net(p->lbl_net);
-#endif
 	kfree(p);
 }
 
@@ -241,7 +238,7 @@
 	newp->label = label;
 	INIT_HLIST_NODE(&newp->list);
 #ifdef CONFIG_NET_NS
-	newp->lbl_net = hold_net(net);
+	newp->lbl_net = net;
 #endif
 	atomic_set(&newp->refcnt, 1);
 	return newp;