offers: fix pay where we are using deprecated apis.

In this case, "fee_base_msat" from `listincoming` has `msat` appended.

Fixes: ElementsProject#5850
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

plugins/offers_invreq_hook.c

@@ -280,6 +280,7 @@ static struct command_result *listincoming_done(struct command *cmd,
 		const jsmntok_t *pftok;
 		u8 *features;
 		const char *err;
+		struct amount_msat feebase;
 
 		err = json_scan(tmpctx, buf, t,
 				"{id:%,"
@@ -295,7 +296,7 @@ static struct command_result *listincoming_done(struct command *cmd,
 				JSON_SCAN(json_to_msat, &ci.capacity),
 				JSON_SCAN(json_to_msat, &ci.htlc_min),
 				JSON_SCAN(json_to_msat, &ci.htlc_max),
-				JSON_SCAN(json_to_u32, &ci.feebase),
+				JSON_SCAN(json_to_msat, &feebase),
 				JSON_SCAN(json_to_u32, &ci.feeppm),
 				JSON_SCAN(json_to_u32, &ci.cltv),
 				JSON_SCAN(json_to_short_channel_id, &ci.scid),
@@ -306,7 +307,7 @@ static struct command_result *listincoming_done(struct command *cmd,
 				   err);
 			continue;
 		}
-
+		ci.feebase = feebase.millisatoshis; /* Raw: feebase */
 		any_public |= ci.public;
 
 		/* Not presented if there's no channel_announcement for peer:

tests/test_pay.py

@@ -4556,7 +4556,6 @@ def test_offer(node_factory, bitcoind):
     assert 'recurrence: every 600 seconds paywindow -10 to +600 (pay proportional)\n' in output
 
 
-@pytest.mark.xfail(strict=True)
 def test_offer_deprecated_api(node_factory, bitcoind):
     l1, l2 = node_factory.line_graph(2, opts={'experimental-offers': None,
                                               'allow-deprecated-apis': True})