Updating copyrights

New format: 'Copyright .year-present Open Networking Laboratory'

Change-Id: I1a9e58b355b775e75245ad875a2d7a4df3f03098
diff --git a/apps/vtn/app/app.xml b/apps/vtn/app/app.xml
index 3bec64d..67092f8 100644
--- a/apps/vtn/app/app.xml
+++ b/apps/vtn/app/app.xml
@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <!--
-  ~ Copyright 2015-2016 Open Networking Laboratory
+  ~ Copyright 2015-present Open Networking Laboratory
   ~
   ~ Licensed under the Apache License, Version 2.0 (the "License");
   ~ you may not use this file except in compliance with the License.
diff --git a/apps/vtn/app/features.xml b/apps/vtn/app/features.xml
index 9ede805..be45842 100644
--- a/apps/vtn/app/features.xml
+++ b/apps/vtn/app/features.xml
@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="UTF-8" standalone="yes"?>
 <!--
-  ~ Copyright 2015 Open Networking Laboratory
+  ~ Copyright 2015-present Open Networking Laboratory
   ~
   ~ Licensed under the Apache License, Version 2.0 (the "License");
   ~ you may not use this file except in compliance with the License.
diff --git a/apps/vtn/app/pom.xml b/apps/vtn/app/pom.xml
index eae39d1..e81dbf9 100644
--- a/apps/vtn/app/pom.xml
+++ b/apps/vtn/app/pom.xml
@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <!--
-  ~ Copyright 2014-2016 Open Networking Laboratory
+  ~ Copyright 2015-present Open Networking Laboratory
   ~
   ~ Licensed under the Apache License, Version 2.0 (the "License");
   ~ you may not use this file except in compliance with the License.