Update TRexClient.java

fix setFlowControlMode

Author: Emil-Gustafsson

src/main/java/com/cisco/trex/stateless/TRexClient.java

@@ -463,7 +463,7 @@ public void setFlowControlMode(int portIndex, int mode) {
     Map<String, Object> payload = createPayload(portIndex);
     Map<String, Object> attributes = new HashMap<>();
     Map<String, Object> flowCtrlValue = new HashMap<>();
-    flowCtrlValue.put("enabled", mode);
+    flowCtrlValue.put("mode", mode);
     attributes.put("flow_ctrl_mode", flowCtrlValue);
     payload.put("attr", attributes);
     callMethod("set_port_attr", payload);