Use 3.4.8 version of OLT deb package for 2.8 release

Change-Id: Ie0106f6dd4610741936167ebdd7e99256d94e7a0
(cherry picked from commit dc8709553377244394f67775e9c16ac737b47c50)
diff --git a/deployment-configs/onf-demo-pod-gpon-DT.yaml b/deployment-configs/onf-demo-pod-gpon-DT.yaml
index 1ca7ab5..4883842 100644
--- a/deployment-configs/onf-demo-pod-gpon-DT.yaml
+++ b/deployment-configs/onf-demo-pod-gpon-DT.yaml
@@ -50,8 +50,8 @@
       fortygig: True
       aggPort: 9
       serial: EC1912001818
-      oltDebVersion: openolt_asgvolt64-3.3.3-1a5d68b50d8bcc5ba6cb1630d3294c30c37cd2f5-40G-NNI.deb
-      oltDebVersion23: openolt_asgvolt64-3.3.3-1a5d68b50d8bcc5ba6cb1630d3294c30c37cd2f5-40G-NNI.deb
+      oltDebVersion: openolt_asgvolt64-3.4.8-eec0fc9e9a01dc0d35b0b8441e0a22a4c0cc51b4-40G-NNI.deb
+      oltDebVersion23: openolt_asgvolt64-3.4.8-eec0fc9e9a01dc0d35b0b8441e0a22a4c0cc51b4-40G-NNI.deb
       board_technology: GPON
 
   hosts: