VOL-2828 Bump post-2.3 release

Change-Id: I1635af0c8a345573fdcb1ae786c1a86e9f0de881
diff --git a/VERSION b/VERSION
index cc6c9a4..eef2640 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-2.3.5
+2.4.0-dev0