GH-824: Fix Log4j2Appender with headers exchange

Fixes #824

**cherry-pick to 2.0.x*

Author: garyrussell

spring-rabbit/src/main/java/org/springframework/amqp/rabbit/log4j2/AmqpAppender.java

@@ -716,7 +716,7 @@ else if ("fanout".equals(this.exchangeType)) {
 					x = new FanoutExchange(this.exchangeName, this.durable, this.autoDelete);
 				}
 				else if ("headers".equals(this.exchangeType)) {
-					x = new HeadersExchange(this.exchangeType, this.durable, this.autoDelete);
+					x = new HeadersExchange(this.exchangeName, this.durable, this.autoDelete);
 				}
 				else {
 					x = new TopicExchange(this.exchangeName, this.durable, this.autoDelete);