GH-1662 Minor cleanup

plugins/chain_plugin/chain_plugin.cpp

@@ -2197,6 +2197,7 @@ void read_write::push_transactions(const read_write::push_transactions_params& p
    } CATCH_AND_CALL(next);
 }
 
+// called from read-exclusive thread for read-only
 template<class API, class Result>
 void api_base::send_transaction_gen(API &api, send_transaction_params_t params, next_function<Result> next) {
    try {

plugins/producer_plugin/producer_plugin.cpp

@@ -2709,7 +2709,7 @@ void producer_plugin_impl::switch_to_read_window() {
 
    // we are in write window, so no read-only trx threads are processing transactions.
    app().get_io_service().poll(); // make sure we schedule any ready
-   if (app().executor().read_exclusive_queue_empty() && app().executor().read_only_queue_empty()) { // no read-only tasks to process. stay in write window
+   if (app().executor().read_only_queue_empty() && app().executor().read_exclusive_queue_empty()) { // no read-only tasks to process. stay in write window
       start_write_window();                          // restart write window timer for next round
       return;
    }