f fudge expected block times

Author: valentinewallace

lightning/src/ln/channelmanager.rs

@@ -10063,7 +10063,8 @@ where
 		let first_hops = self.list_usable_channels();
 		let payee_node_id = self.get_our_node_id();
 
-		const SECONDS_PER_BLOCK: u32 = 10 * 60;
+		// Assume shorter than usual block times to avoid spuriously failing payments too early.
+		const SECONDS_PER_BLOCK: u32 = 9 * 60;
 		let relative_expiry_blocks = relative_expiry_seconds / SECONDS_PER_BLOCK;
 		let max_cltv_expiry = core::cmp::max(relative_expiry_blocks, CLTV_FAR_FAR_AWAY)
 			.saturating_add(LATENCY_GRACE_PERIOD_BLOCKS)