Moving to released ONOS 2.2.1

Change-Id: Ib0aec16e89a0119970b88323ccd120c6070ea10b
diff --git a/VERSION b/VERSION
index ad6abd3..1454f6e 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-4.0.1-dev
+4.0.1