opts: Bump max_fee_multiplier to 10x

The fee range can sometimes cause channels to be closed when the estimator
jumps. This has been the case a few times in the last months, and causes a
number of channels to be closed, and issue reports to be filed.

Increasing this from 5x to 10x should get rid of 84%+ of these
closures (measured based on 1h windows over the last 6 months and assuming
worst case situations).

Signed-off-by: Christian Decker <decker.christian@gmail.com>

lightningd/options.c

@@ -524,7 +524,7 @@ static const struct config testnet_config = {
 	.rescan = 30,
 
 	/* Fees may be in the range our_fee - 10*our_fee */
-	.max_fee_multiplier = 5,
+	.max_fee_multiplier = 10,
 };
 
 /* aka. "Dude, where's my coins?" */
@@ -580,7 +580,7 @@ static const struct config mainnet_config = {
 	.rescan = 15,
 
 	/* Fees may be in the range our_fee - 10*our_fee */
-	.max_fee_multiplier = 5,
+	.max_fee_multiplier = 10,
 };
 
 static void check_config(struct lightningd *ld)