[NETNS]: Declare init_net even without CONFIG_NET defined.

This does not look good, but there is no other choice. The compilation
without CONFIG_NET is broken and can not be fixed with ease.

After that there is no need for the following commits:
1567ca7eec7664b8be3b07755ac59dc1b1ec76cb
3edf8fa5ccf10688a9280b5cbca8ed3947c42866
2d38f9a4f8d2ebdc799f03eecf82345825495711

Revert them.

Signed-off-by: Denis V. Lunev <den@openvz.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/net/net_namespace.h b/include/net/net_namespace.h
index 6c9a48a..0ab62ed 100644
--- a/include/net/net_namespace.h
+++ b/include/net/net_namespace.h
@@ -60,11 +60,12 @@
 };
 
 
-#ifdef CONFIG_NET
 #include <linux/seq_file_net.h>
 
 /* Init's network namespace */
 extern struct net init_net;
+
+#ifdef CONFIG_NET
 #define INIT_NET_NS(net_ns) .net_ns = &init_net,
 
 extern struct net *copy_net_ns(unsigned long flags, struct net *net_ns);