INT-2474: MGS: logging Exception at debug level

JIRA: https://jira.spring.io/browse/INT-2474

spring-integration-core/src/main/java/org/springframework/integration/gateway/MessagingGatewaySupport.java

@@ -254,7 +254,9 @@ public abstract class MessagingGatewaySupport extends AbstractEndpoint implement
 			}
 		}
 		catch (Exception e) {
-			logger.warn("failure occurred in gateway sendAndReceive", e);
+			if (logger.isDebugEnabled()) {
+				logger.debug("failure occurred in gateway sendAndReceive: " + e.getMessage());
+			}
 			error = e;
 		}