Merge #908: gui(daemon): fix rbfpsbt params for external daemon

5c06eef gui(daemon): fix rbfpsbt params for external daemon (jp1ac4)

Pull request description:

  The `is_cancel` parameter gives an "invalid parameter" error when converted to string.

  The `feerate_vb` parameter should only be passed if it has a value as otherwise it gives an "invalid parameter" error.

ACKs for top commit:
  edouardparis:
    utACK 5c06eef

Tree-SHA512: 73d192186ffac19c560cf7dd0aef8ae5c276bc6ff09852d7b1bc59aa23fe9f980c11e53654fc20fdc41ab2fee9f4433a91591c869ba0aebade8f2febce2121b5

gui/src/daemon/client/mod.rs

@@ -102,14 +102,11 @@ impl<C: Client + Debug> Daemon for Lianad<C> {
         is_cancel: bool,
         feerate_vb: Option<u64>,
     ) -> Result<CreateSpendResult, DaemonError> {
-        self.call(
-            "rbfpsbt",
-            Some(vec![
-                json!(txid.to_string()),
-                json!(is_cancel.to_string()),
-                json!(feerate_vb),
-            ]),
-        )
+        let mut input = vec![json!(txid.to_string()), json!(is_cancel)];
+        if let Some(feerate_vb) = feerate_vb {
+            input.push(json!(feerate_vb));
+        }
+        self.call("rbfpsbt", Some(input))
     }
 
     fn update_spend_tx(&self, psbt: &Psbt) -> Result<(), DaemonError> {