[NETNS][FRAGS]: Make the mem counter per-namespace.

This is also simple, but introduces more changes, since
then mem counter is altered in more places.

Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv6/proc.c b/net/ipv6/proc.c
index dec34c8..35e502a 100644
--- a/net/ipv6/proc.c
+++ b/net/ipv6/proc.c
@@ -44,7 +44,7 @@
 	seq_printf(seq, "RAW6: inuse %d\n",
 		       sock_prot_inuse_get(&rawv6_prot));
 	seq_printf(seq, "FRAG6: inuse %d memory %d\n",
-		       ip6_frag_nqueues(&init_net), ip6_frag_mem());
+		       ip6_frag_nqueues(&init_net), ip6_frag_mem(&init_net));
 	return 0;
 }