Add 20min timeout for 'stack delete' operation

It allows to avoid hanging script when satck deletion completes with
DELETE_FAILED state

Change-Id: I79d83a90965b58835e11bef07228915fd9571093
Realted-Prod:#PROD-33974(PROD:33974)
diff --git a/jobs/pipelines/swarm-bootstrap-salt-cluster-heat.groovy b/jobs/pipelines/swarm-bootstrap-salt-cluster-heat.groovy
index 1ea4d5c..a4903c8 100644
--- a/jobs/pipelines/swarm-bootstrap-salt-cluster-heat.groovy
+++ b/jobs/pipelines/swarm-bootstrap-salt-cluster-heat.groovy
@@ -82,7 +82,7 @@
                     # export OS_PASSWORD=${OS_PASSWORD}
                     # export OS_PROJECT_NAME=${OS_PROJECT_NAME}
                     openstack --insecure stack delete -y ${ENV_NAME} || true
-                    while openstack --insecure stack show ${ENV_NAME} -f value -c stack_status; do sleep 10; done
+                    timeout 20m /bin/bash -c "while openstack --insecure stack show ${ENV_NAME} -f value -c stack_status; do sleep 10; done"
                 """)
 
                 println "Remove config drive ISO"