xfrm: Using the right namespace to migrate key info

because the home agent could surely be run on a different
net namespace other than init_net. The original behavior
could lead into inconsistent of key info.

Signed-off-by: Fan Du <fan.du@windriver.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
diff --git a/net/key/af_key.c b/net/key/af_key.c
index 545f047..3fa811c 100644
--- a/net/key/af_key.c
+++ b/net/key/af_key.c
@@ -2485,6 +2485,7 @@
 	struct xfrm_selector sel;
 	struct xfrm_migrate m[XFRM_MAX_DEPTH];
 	struct xfrm_kmaddress k;
+	struct net *net = sock_net(sk);
 
 	if (!present_and_same_family(ext_hdrs[SADB_EXT_ADDRESS_SRC - 1],
 				     ext_hdrs[SADB_EXT_ADDRESS_DST - 1]) ||
@@ -2558,7 +2559,7 @@
 	}
 
 	return xfrm_migrate(&sel, dir, XFRM_POLICY_TYPE_MAIN, m, i,
-			    kma ? &k : NULL);
+			    kma ? &k : NULL, net);
 
  out:
 	return err;