Releasing official voltha-onos for 2.9 with ONOS 2.5.5

Change-Id: I3c6d941f242cf5a09b1194cc46b453b19f03d085
diff --git a/VERSION b/VERSION
index 403e252..2d6c0bc 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-5.0.4-dev8
+5.0.4