Fetching images from ci-registry for voltha verify jobs

Change-Id: I62d0dacde5f3c4d827d1a4158730668aefb27418
diff --git a/jjb/pipeline/voltha-bbsim-tests.groovy b/jjb/pipeline/voltha-bbsim-tests.groovy
index fec9c23..d45dc83 100644
--- a/jjb/pipeline/voltha-bbsim-tests.groovy
+++ b/jjb/pipeline/voltha-bbsim-tests.groovy
@@ -33,6 +33,7 @@
     NAME="test"
     VOLTCONFIG="$HOME/.volt/config-$NAME"
     KUBECONFIG="$HOME/.kube/kind-config-voltha-$NAME"
+    EXTRA_HELM_FLAGS=" --set defaults.image_registry=https://mirror.registry.opennetworking.org"
   }
 
   stages {