Apply the extraHelmFlags after sourcing the release file in the scale job

Change-Id: I5d423225aea36370ad4e05f8d670cdccc812524f
diff --git a/jjb/pipeline/voltha-scale-test.groovy b/jjb/pipeline/voltha-scale-test.groovy
index 413e5eb..0cf443c 100644
--- a/jjb/pipeline/voltha-scale-test.groovy
+++ b/jjb/pipeline/voltha-scale-test.groovy
@@ -178,6 +178,7 @@
             # Load the release defaults
             if [ '${release.trim()}' != 'master' ]; then
               source $WORKSPACE/kind-voltha/releases/${release}
+              EXTRA_HELM_FLAGS+=" ${extraHelmFlags} "
             fi
 
             # BBSim custom image handling
@@ -221,6 +222,9 @@
             # No persistent-volume-claims in Atomix
             EXTRA_HELM_FLAGS+="--set atomix.persistence.enabled=false "
 
+            echo "Installing with the following extra arguments:"
+            echo $EXTRA_HELM_FLAGS
+
             ./voltha up
 
             # Forward the ETCD port onto $VOLTHA_ETCD_PORT