Customize flags for adtran openolt adapter image

Change-Id: I0b442385f852c7d971f4f80fbb733fc8e0be231b
diff --git a/kubernetes-configs/voltha/dt-berlin-pod-gpon-adtran.yml b/kubernetes-configs/voltha/dt-berlin-pod-gpon-adtran.yml
index cfee07c..8d8e672 100644
--- a/kubernetes-configs/voltha/dt-berlin-pod-gpon-adtran.yml
+++ b/kubernetes-configs/voltha/dt-berlin-pod-gpon-adtran.yml
@@ -25,6 +25,8 @@
 images:
   adapter_adtran_olt:
     registry: "10.34.90.43:443/"
+    repository: ''
+    tag: "1.4.0"
 
 
 deployments: