Update setUsePublisherConnection javadocs (#1100)

* Set default of usePublisherConnection to true

Docs in setUsePublisherConnection say this defaults to true since version 2.1 what, in my opinion, is not true

* Update javadocs for setUsePublisherConnection setter

Author: kjastrzebski

spring-rabbit/src/main/java/org/springframework/amqp/rabbit/core/RabbitTemplate.java

@@ -794,8 +794,7 @@ public boolean isUsePublisherConnection() {
 	/**
 	 * To avoid deadlocked connections, it is generally recommended to use
 	 * a separate connection for publishers and consumers (except when a publisher
-	 * is participating in a consumer transaction). Default 'false'; will change
-	 * to 'true' in 2.1.
+	 * is participating in a consumer transaction). Default 'false'.
 	 * @param usePublisherConnection true to use a publisher connection.
 	 * @since 2.0.2
 	 */