fix: fixed header of AUTH packet

Associated with contributions from
  #980
  #981

Signed-off-by: Li Zhanhui <lizhanhui@gmail.com>

Author: lizhanhui

org.eclipse.paho.mqttv5.client/src/main/java/org/eclipse/paho/mqttv5/client/internal/ClientComms.java

@@ -41,6 +41,7 @@
 import org.eclipse.paho.mqttv5.common.MqttException;
 import org.eclipse.paho.mqttv5.common.MqttMessage;
 import org.eclipse.paho.mqttv5.common.MqttPersistenceException;
+import org.eclipse.paho.mqttv5.common.packet.MqttAuth;
 import org.eclipse.paho.mqttv5.common.packet.MqttConnAck;
 import org.eclipse.paho.mqttv5.common.packet.MqttConnect;
 import org.eclipse.paho.mqttv5.common.packet.MqttDisconnect;
@@ -176,8 +177,9 @@ void internalSend(MqttWireMessage message, MqttToken token) throws MqttException
 	public void sendNoWait(MqttWireMessage message, MqttToken token) throws MqttException {
 		final String methodName = "sendNoWait";
 
-		if (isConnected() || (!isConnected() && message instanceof MqttConnect)
-				|| (isDisconnecting() && message instanceof MqttDisconnect)) {
+		if (isConnected() ||
+				(!isConnected() && (message instanceof MqttConnect || message instanceof MqttAuth)) ||
+				(isDisconnecting() && message instanceof MqttDisconnect)) {
 
 			if (disconnectedMessageBuffer != null && disconnectedMessageBuffer.getMessageCount() != 0) {
 				// @TRACE 507=Client Connected, Offline Buffer available, but not empty. Adding

org.eclipse.paho.mqttv5.client/src/main/java/org/eclipse/paho/mqttv5/client/internal/ClientState.java

@@ -841,8 +841,15 @@ protected MqttWireMessage get() throws MqttException {
 				// Handle the case where not connected. This should only be the case if:
 				// - in the process of disconnecting / shutting down
 				// - in the process of connecting
-				if (pendingFlows == null || (!connected && (pendingFlows.isEmpty()
-						|| !((MqttWireMessage) pendingFlows.elementAt(0) instanceof MqttConnect)))) {
+				if (pendingFlows == null ||
+						(!connected &&
+								(pendingFlows.isEmpty() ||
+										!( ( pendingFlows.elementAt(0) instanceof MqttConnect) ||
+												( pendingFlows.elementAt(0) instanceof MqttAuth)
+										)
+								)
+						)
+				){
 					// @TRACE 621=no outstanding flows and not connected
 					log.fine(CLASS_NAME, methodName, "621");
 

org.eclipse.paho.mqttv5.client/src/main/java/org/eclipse/paho/mqttv5/common/packet/MqttAuth.java

@@ -104,7 +104,7 @@ protected byte[] getVariableHeader() throws MqttException {
 
 	@Override
 	protected byte getMessageInfo() {
-		return (byte) (1);
+		return (byte) (0);
 	}
 
 	public int getReturnCode() {