[NETNS][FRAGS]: Isolate the secret interval from namespaces.

Since we have one hashtable to lookup the fragment, having
different secret_interval-s for hash rebuild doesn't make
sense, so move this one to inet_frags.

The inet_frags_ctl becomes empty after this, so remove it.
The appropriate ctl table is kept read-only in namespaces.

Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/net/inet_frag.h b/include/net/inet_frag.h
index de41359..1917fbe 100644
--- a/include/net/inet_frag.h
+++ b/include/net/inet_frag.h
@@ -31,18 +31,14 @@
 
 #define INETFRAGS_HASHSZ		64
 
-struct inet_frags_ctl {
-	int secret_interval;
-};
-
 struct inet_frags {
 	struct list_head	lru_list;
 	struct hlist_head	hash[INETFRAGS_HASHSZ];
 	rwlock_t		lock;
 	u32			rnd;
 	int			qsize;
+	int			secret_interval;
 	struct timer_list	secret_timer;
-	struct inet_frags_ctl	*ctl;
 
 	unsigned int		(*hashfn)(struct inet_frag_queue *);
 	void			(*constructor)(struct inet_frag_queue *q,