Movign to 2.5.7-rc2 and including DT FTTB workflow changes in sadis, olt, dhcpl2relay

Change-Id: Ic07c052c9803a839a23976977d33e58b28523d7c
diff --git a/VERSION b/VERSION
index 94a5b9e..5965777 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-5.1.0-dev7
+5.1.0-dev8