Post release increment to version 2.1.1-dev

Change-Id: I21652f6b1c602bbd7daaf84b5eaf5619901c7257
diff --git a/VERSION b/VERSION
index 7ec1d6d..7c7e096 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-2.1.0
+2.1.1-dev