lightningd: remove deprecated return for `db_write` hook.

Changelog-Removed: JSON API: The hook `db_write` can no longer return `true` (deprecated in 0.8.1)
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

lightningd/plugin_hook.c

@@ -299,33 +299,6 @@ static void db_hook_response(const char *buffer, const jsmntok_t *toks,
 		fatal("Plugin returned an invalid response to the db_write "
 		      "hook: %s", buffer);
 
-#ifdef COMPAT_V080
-	/* For back-compatibility we allow to return a simple Boolean true.  */
-	if (deprecated_apis) {
-		bool resp;
-		if (json_to_bool(buffer, resulttok, &resp)) {
-			static bool warned = false;
-			/* If it fails, we must not commit to our db. */
-			if (!resp)
-				fatal("Plugin returned failed db_write: %s.",
-				      buffer);
-			if (!warned) {
-				warned = true;
-				log_unusual(ph_req->db->log,
-					    "Plugin returned 'true' to "
-					    "'db_hook'.  "
-					    "This is now deprecated and "
-					    "you should return "
-					    "{'result': 'continue'} "
-					    "instead.");
-			}
-			/* Resume.  */
-			io_break(ph_req);
-			return;
-		}
-	}
-#endif /* defined(COMPAT_V080) */
-
 	/* We expect result: { 'result' : 'continue' }.
 	 * Anything else we abort.
 	 */