MXS-2139: Extend transaction_replay requirements

Enabling transaction_replay now automatically enables
master_failure_mode=fail_on_write. This makes the behavior consistent
across all failure modes.

server/modules/routing/readwritesplit/readwritesplit.hh

@@ -193,6 +193,7 @@ struct Config
              */
             delayed_retry = true;
             master_reconnection = true;
+            master_failure_mode = RW_FAIL_ON_WRITE;
         }
     }