One should have an ability to set up max_nested_stack_depth option

Customer requires from us to set up max_nested_stack_depth in
heat.conf.

This option is not enabled and has value of 5 by default.
We need to enable this option in templates so customer would be
able to set it to a desired value.

Customer-Found
PROD-15878
Change-Id: I9fba7f44a595a33b78ea31e21f90eeb2f62c7fb0
diff --git a/tests/pillar/server_cluster.sls b/tests/pillar/server_cluster.sls
index 0c5f303..14f0750 100644
--- a/tests/pillar/server_cluster.sls
+++ b/tests/pillar/server_cluster.sls
@@ -59,3 +59,4 @@
       'cloudformation:ValidateTemplate': 'rule:deny_stack_user'
       'cloudformation:DescribeStackResource':
     max_stacks_per_tenant: 150
+    max_nested_stack_depth: 10