openingd: make channel-type rejection message clearer.

For example, lnprototest got the error 'You gave bad parameters: Did not support channel_type ' which doesn't make it clear that it's rejecting the empty channel type.

Signed-off-by: Rusty Russell <[email protected]>

Author: rustyrussell

openingd/dualopend.c

@@ -2433,7 +2433,7 @@ static void accepter_start(struct state *state, const u8 *oc2_msg)
 				state->channel_type = channel_type_from(state, open_tlv->channel_type);
 			} else {
 				negotiation_failed(state,
-						   "Did not support channel_type %s",
+						   "Did not support channel_type [%s]",
 						   fmt_featurebits(tmpctx,
 								   open_tlv->channel_type));
 				return;

openingd/openingd.c

@@ -974,7 +974,7 @@ static u8 *fundee_channel(struct state *state, const u8 *open_channel_msg)
 				state->channel_type = channel_type_from(state, open_tlvs->channel_type);
 			} else {
 				negotiation_failed(state,
-						   "Did not support channel_type %s",
+						   "Did not support channel_type [%s]",
 						   fmt_featurebits(tmpctx,
 								   open_tlvs->channel_type));
 				return NULL;