pay: remove description_hash without description.

Deprecated v0.11.0.

Changelog-Removed: JSON-RPC: `pay` for a bolt11 which uses a `description_hash`, without setting `description` (deprecated v0.11.0).
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

Author: rustyrussell

doc/lightning-pay.7.md

@@ -44,7 +44,8 @@ implement your own heuristics rather than the primitive ones used
 here.
 
 *description* is only required for bolt11 invoices which do not
-contain a description themselves, but contain a description hash.
+contain a description themselves, but contain a description hash:
+in this case *description* is required.
 *description* is then checked against the hash inside the invoice
 before it will be paid.
 

plugins/pay.c

@@ -1066,7 +1066,7 @@ static struct command_result *json_pay(struct command *cmd,
 		 * - MUST check that the SHA2 256-bit hash in the `h` field
 		 *   exactly matches the hashed description.
 		 */
-		if (!b11->description && !deprecated_apis) {
+		if (!b11->description) {
 			if (!b11->description_hash) {
 				return command_fail(cmd,
 						    JSONRPC2_INVALID_PARAMS,