MDEV-34682 Return the return value of ddl recovery done in ha_initialize_handlerton

Otherwise it could cause false negative when ddl recovery done is part
of the plugin initialization

sql/handler.cc

@@ -782,7 +782,7 @@ int ha_initialize_handlerton(st_plugin_int *plugin)
   update_discovery_counters(hton, 1);
 
   if (ddl_recovery_done && hton->signal_ddl_recovery_done)
-    hton->signal_ddl_recovery_done(hton);
+    ret= hton->signal_ddl_recovery_done(hton);
 
   DBUG_RETURN(ret);
 

storage/spider/spd_table.cc

@@ -6511,8 +6511,10 @@ bool spider_init_system_tables()
 
 
 /*
-  Spider is typically loaded before ddl_recovery, but DDL statements
-  cannot be executed before ddl_recovery, so we delay system table creation.
+  Spider may be loaded before ddl_recovery (e.g. with
+  --plugin-load-add), but DDL statements in spider init queries cannot
+  be executed before ddl_recovery, so we execute these queries only
+  after ddl recovery.
 */
 static int spider_after_ddl_recovery(handlerton *)
 {