fixed compiler error in 5.1-marvel.

sql/sql_plugin.cc

@@ -1448,7 +1448,6 @@ static bool plugin_load_list(MEM_ROOT *tmp_root, int *argc, char **argv,
             if (plugin_add(tmp_root, &name, &dl, argc, argv, REPORT_TO_LOG))
               goto error;
           }
-          }
           plugin_dl_del(&dl); // reduce ref count
         }
       }