Using test image in DT scale test

Change-Id: I066b904e43a55f68bee7267977ce1a36b1e5deb0
diff --git a/jjb/voltha-scale.yaml b/jjb/voltha-scale.yaml
index efd6b59..28b274d 100644
--- a/jjb/voltha-scale.yaml
+++ b/jjb/voltha-scale.yaml
@@ -264,6 +264,7 @@
           release: voltha-2.4
           karafHome: apache-karaf-4.2.8
           logLevel: INFO
+          openoltAdapterImg: matteoscandolo/voltha-rw-core:per-gem-lock
 
       # development pipeline
       - 'voltha-scale-measurements-dev':