[NETNS][IPV6]: Make bindv6only sysctl per namespace.

This patch moves the bindv6only sysctl to the network namespace
structure. Until the ipv6 protocol is not per namespace, the sysctl
variable is always from the initial network namespace.

Signed-off-by: Daniel Lezcano <dlezcano@fr.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/net/netns/ipv6.h b/include/net/netns/ipv6.h
index 58fbf30..42b9b41 100644
--- a/include/net/netns/ipv6.h
+++ b/include/net/netns/ipv6.h
@@ -11,6 +11,7 @@
 #ifdef CONFIG_SYSCTL
 	struct ctl_table_header *table;
 #endif
+	int bindv6only;
 };
 
 struct netns_ipv6 {