Wrong ONOS image for adtran 2.8 job

Change-Id: Ib30f773b37f04cdecbc3d3e122f7be5b8141ffb0
diff --git a/jjb/voltha-test/voltha.yaml b/jjb/voltha-test/voltha.yaml
index 87c55b3..f68a138 100644
--- a/jjb/voltha-test/voltha.yaml
+++ b/jjb/voltha-test/voltha.yaml
@@ -546,7 +546,7 @@
           branch: 'voltha-2.8'
           profile: '1T8GEM'
           reinstall-olt: false
-          extraHelmFlags: "--set adapter_adtran_olt.kv_store_data_prefix='service/voltha/voltha_voltha' --set network.netconfUserSecret='' --set adapter_adtran_olt.topics.core_topic=voltha_voltha_rwcore --set onos-classic.image.tag=master"
+          extraHelmFlags: "--set adapter_adtran_olt.kv_store_data_prefix='service/voltha/voltha_voltha' --set network.netconfUserSecret='' --set adapter_adtran_olt.topics.core_topic=voltha_voltha_rwcore"
           num-of-onos: '3'
           num-of-atomix: '3'
           pipeline-script: 'voltha/voltha-2.8/physical-build.groovy'