AMQNET-562 Update NOTICE file

Updates
diff --git a/NOTICE.txt b/NOTICE.txt
index 1c50c18..98c5275 100644
--- a/NOTICE.txt
+++ b/NOTICE.txt
@@ -5,7 +5,7 @@
 =========================================================================
 
 Apache ActiveMQ
-Copyright 2005-2017 The Apache Software Foundation
+Copyright 2005-2017 The Apache Software Foundation.
 
 This product includes software developed by
 The Apache Software Foundation (http://www.apache.org/).