Add golang notes to release checklist.  Add version strings for sadis, aaa and dhcpl2relay in release notes

Change-Id: Ia1719de83ed7d2c0a1fee96bfc31369ef448e358
diff --git a/VERSION b/VERSION
index faad078..198d0ef 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-2.12.4.1
+2.12.4.2-dev