Move salt formulas test to xenial jenkins node

Currently some tests are not build-able on jenkins bionic nodes

Related-bug: PROD-36062
Change-Id: I99990428ae976f2e8ee9d9d091c1a5fb7f0796c4
diff --git a/test-salt-formulas-env.groovy b/test-salt-formulas-env.groovy
index 43d318c..c526a51 100644
--- a/test-salt-formulas-env.groovy
+++ b/test-salt-formulas-env.groovy
@@ -27,6 +27,8 @@
   env.GERRIT_BRANCH = GERRIT_PARENT_BRANCH
 }
 
+def nodeLabel = 'old16.04'
+
 def checkouted = false
 def openstackTest = false
 def travisLess = false      /** TODO: Remove once formulas are witched to new config */
@@ -37,7 +39,7 @@
 
 throttle(['test-formula']) {
   timeout(time: 1, unit: 'HOURS') {
-    node("python&&docker") {
+    node(nodeLabel) {
       try {
         stage("checkout") {
           if (defaultGitRef && defaultGitUrl) {