Pin some reclass model tests to old jenkins nodes

PROD-36373

Change-Id: Id7e9624efddc79a3ebd43a1903921265adfd1759
diff --git a/test-cookiecutter-reclass.groovy b/test-cookiecutter-reclass.groovy
index d018a50..605d531 100644
--- a/test-cookiecutter-reclass.groovy
+++ b/test-cookiecutter-reclass.groovy
@@ -27,7 +27,7 @@
     extraVars = [:]
 }
 
-slaveNode = env.SLAVE_NODE ?: 'virtual'
+slaveNode = env.SLAVE_NODE ?: 'old16.04'
 checkIncludeOrder = env.CHECK_INCLUDE_ORDER ?: false
 
 // Global var's