xpay: age askrene entries older than 1 week

We have set an exponential decay time for liquidity bounds with a
lifetime of 1 day, it halves every 16 hours. This parameter can be
tuned. But I think throwing away entries after 1 hour is too aggresive.
Better to remove them after 1 week. In that time it will be halved 10
times.

Changelog-None

Signed-off-by: Lagrang3 <lagrang3@protonmail.com>

Author: Lagrang3

plugins/xpay/xpay.c

@@ -31,6 +31,9 @@
 
 #define PREIMAGE_TLV_TYPE 5482373484
 
+/* Entries older than 1 week are thrown away. */
+#define XPAY_AGE_TIME_SECS 604800
+
 /* For the whole plugin */
 struct xpay {
 	/* This is me. */
@@ -2966,7 +2969,7 @@ static struct command_result *age_layer(struct command *cmd, struct payment *pay
 				    plugin_broken_cb,
 				    payment);
 	json_add_string(req->js, "layer", "xpay");
-	json_add_u64(req->js, "cutoff", clock_time().ts.tv_sec - 3600);
+	json_add_u64(req->js, "cutoff", clock_time().ts.tv_sec - XPAY_AGE_TIME_SECS);
 	return send_outreq(req);
 }