[NETNS]: Refactor fib initialization so it can handle multiple namespaces.

This patch makes the fib to be initialized as a subsystem for the
network namespaces. The code does not handle several namespaces yet,
so in case of a creation of a network namespace, the
creation/initialization will not occur.

Acked-by: Benjamin Thery <benjamin.thery@bull.net>
Acked-by: Daniel Lezcano <dlezcano@fr.ibm.com>
Signed-off-by: Denis V. Lunev <den@openvz.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/net/ip_fib.h b/include/net/ip_fib.h
index cbff18d..338d3ed 100644
--- a/include/net/ip_fib.h
+++ b/include/net/ip_fib.h
@@ -186,7 +186,8 @@
 }
 
 #else /* CONFIG_IP_MULTIPLE_TABLES */
-extern int __init fib4_rules_init(void);
+extern int __net_init fib4_rules_init(struct net *net);
+extern void __net_exit fib4_rules_exit(struct net *net);
 
 #ifdef CONFIG_NET_CLS_ROUTE
 extern u32 fib_rules_tclass(struct fib_result *res);