[VOL-3107] Add DeleteGroup API to OpenOLT Agent

- DeleteGroup proto API method implemented.
- Unit tests added.

Change-Id: If196a92f7a717fc4cc6c2f0e0bb6ca74fc3683d2
diff --git a/VERSION b/VERSION
index 1a45714..bfa64e9 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-2.4.9-dev
+2.4.10-dev