VOL-2400 Fix KeyError when no data field in OMCI message

Change-Id: I040e7c62fd03c4b2593575673e2f6aeb0cfb00f6
diff --git a/VERSION b/VERSION
index 1c1ea95..be14458 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-2.3.15_dev
+2.3.15