Using correct core image in new olt-app voltha scale job

Change-Id: Id3909a93bab2931d9892ee62adfeacd95dbef23a
diff --git a/jjb/voltha-scale.yaml b/jjb/voltha-scale.yaml
index aeb7ce4..336a67f 100644
--- a/jjb/voltha-scale.yaml
+++ b/jjb/voltha-scale.yaml
@@ -158,7 +158,7 @@
           withIgmp: false
           inMemoryEtcdStorage: false
           extraHelmFlags: '--set authRetry=false,dhcpRetry=false -f /home/jenkins/voltha-scale/voltha-values.yaml'
-          rwCoreImg: 'matteoscandolo/voltha-rw-core:test'
+          rwCoreImg: 'matteoscandolo/voltha-rw-core:sync-delete'
           ofAgentImg: 'matteoscandolo/voltha-ofagent-go:test'
           onosImg: 'matteoscandolo/voltha-onos:oltapp'