net sysctl: Initialize the network sysctls sooner to avoid problems.

If the netfilter code is modified to use register_net_sysctl_table the
kernel fails to boot because the per net sysctl infrasturce is not setup
soon enough.  So to avoid races call net_sysctl_init from sock_init().

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Acked-by: Pavel Emelyanov <xemul@parallels.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/net/net_namespace.h b/include/net/net_namespace.h
index 446245e..767dcd40 100644
--- a/include/net/net_namespace.h
+++ b/include/net/net_namespace.h
@@ -283,6 +283,11 @@
 struct ctl_table;
 struct ctl_table_header;
 
+#ifdef CONFIG_SYSCTL
+extern int net_sysctl_init(void);
+#else
+static inline int net_sysctl_init(void) { return 0; }
+#endif
 extern struct ctl_table_header *register_net_sysctl_table(struct net *net,
 	const struct ctl_path *path, struct ctl_table *table);
 extern struct ctl_table_header *register_net_sysctl_rotable(