Reduce parralellism for testing

Change-Id: Iec9c13a8dd926df937d8846448b64f1f0b402dd7
diff --git a/jenkins/client/job/salt-models/tests.yml b/jenkins/client/job/salt-models/tests.yml
index 815526e..4b6c006 100644
--- a/jenkins/client/job/salt-models/tests.yml
+++ b/jenkins/client/job/salt-models/tests.yml
@@ -41,7 +41,7 @@
                 default: "gerrit"
               PARALLEL_NODE_GROUP_SIZE:
                 type: string
-                default: "5"
+                default: "2"
               # Salt master setup extra formulas
               EXTRA_FORMULAS:
                 type: string