Adding 2.5 image for DT as well at scale

Change-Id: I0036e359d8439c39b1794d00578a7e8877defdd0
diff --git a/jjb/voltha-scale.yaml b/jjb/voltha-scale.yaml
index c054050..ca1d45f 100644
--- a/jjb/voltha-scale.yaml
+++ b/jjb/voltha-scale.yaml
@@ -80,6 +80,7 @@
           withDhcp: false
           withIgmp: false
           extraHelmFlags: '--set authRetry=true,dhcpRetry=true --set global.log_correlation.enabled=true -f /home/jenkins/voltha-scale/voltha-values.yaml '
+          onosImg: andreacampanella/voltha-onos:voltha-onos-2.5
 
       - 'voltha-scale-measurements':
           name: 'voltha-scale-measurements-master-2-16-32-tt-subscribers'