INT-1307 Remove Java 6 dependency (cause in IOException)

spring-integration-core/src/main/java/org/springframework/commons/serializer/java/JavaStreamingConverter.java

@@ -49,7 +49,7 @@ public class JavaStreamingConverter
 			if (objectInputStream != null) {
 				objectInputStream.close();
 			}
-			throw new IOException(e);
+			throw new IOException(e.getMessage());
 		}
 	}