changing node executor size for voltha-unit tests

Change-Id: I2614b2ef4412a41001174845689e2906c9206064
diff --git a/jjb/voltha-unit-test.yaml b/jjb/voltha-unit-test.yaml
index 22b4456..d6bf304 100644
--- a/jjb/voltha-unit-test.yaml
+++ b/jjb/voltha-unit-test.yaml
@@ -35,7 +35,7 @@
           choosing-strategy: gerrit
           jenkins-ssh-credential: '{jenkins-ssh-credential}'
 
-    node: 'ubuntu16.04-basebuild-4c-8g'
+    node: 'ubuntu16.04-basebuild-2c-4g'
     project-type: freestyle
     concurrent: true