Convert workerThreads toString for isInteger check

PROD-32912

Change-Id: Ib781258c8f7e49deecbe3be16458065be74652b3
diff --git a/cloud-deploy-pipeline.groovy b/cloud-deploy-pipeline.groovy
index 4159655..0713192 100644
--- a/cloud-deploy-pipeline.groovy
+++ b/cloud-deploy-pipeline.groovy
@@ -356,7 +356,7 @@
             // Install
             //
             if (!batch_size) {
-                def workerThreads = salt.getReturnValues(salt.getPillar(venvPepper, "I@salt:master", "salt:master:worker_threads", null))
+                def workerThreads = salt.getReturnValues(salt.getPillar(venvPepper, "I@salt:master", "salt:master:worker_threads", null)).toString()
                 if (workerThreads.isInteger() && workerThreads.toInteger() > 0) {
                    batch_size = workerThreads
                 }