Updating DHCP-l2-relay app version to 2.2.1
and voltha-onos to 4.1.6

Change-Id: I3bad721d6d922dfd6ef2b88b525889f4268e2527
diff --git a/VERSION b/VERSION
index b1cbc1f..561ad33 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-4.1.5
+4.1.6