VERSION bump to 2.2.4-dev

Change-Id: Ic1d032138674ec5c68613117fb32b446f713a8ea
diff --git a/VERSION b/VERSION
index 5859406..bdbe651 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-2.2.3
+2.2.4-dev