af_key: initialize satype in key_notify_policy_flush()

This field was left uninitialized. Some user daemons perform check against this
field.
Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>

net/key/af_key.c

@@ -2694,6 +2694,7 @@ static int key_notify_policy_flush(const struct km_event *c)
 	hdr->sadb_msg_pid = c->portid;
 	hdr->sadb_msg_version = PF_KEY_V2;
 	hdr->sadb_msg_errno = (uint8_t) 0;
+	hdr->sadb_msg_satype = SADB_SATYPE_UNSPEC;
 	hdr->sadb_msg_len = (sizeof(struct sadb_msg) / sizeof(uint64_t));
 	pfkey_broadcast(skb_out, GFP_ATOMIC, BROADCAST_ALL, NULL, c->net);
 	return 0;