Fetching images from ci-registry for voltha verify jobs

Change-Id: I62d0dacde5f3c4d827d1a4158730668aefb27418
diff --git a/jjb/pipeline/voltha-openonu-go-tests.groovy b/jjb/pipeline/voltha-openonu-go-tests.groovy
index e41a9a2..27768bd 100755
--- a/jjb/pipeline/voltha-openonu-go-tests.groovy
+++ b/jjb/pipeline/voltha-openonu-go-tests.groovy
@@ -39,6 +39,7 @@
     CONFIG_SADIS="external"
     BBSIM_CFG="configs/bbsim-sadis-att.yaml"
     ROBOT_MISC_ARGS="-d $WORKSPACE/RobotLogs"
+    EXTRA_HELM_FLAGS=" --set defaults.image_registry=https://mirror.registry.opennetworking.org"
   }
   stages {
     stage('Clone kind-voltha') {