[DNM] Tuning stack_retries of k8s FT in Zuul

Due to the performance of the zuul environment, it may take a long time
to remove the kubernetes resource and an error may occur.
This patch avoids errors by tuning the `kubernetes_vim.stack_retries`
value in Tacker config.

Change-Id: I0fc8d6748cf92f6384b6cdc49322f0f85f16afcd

.zuul.yaml

@@ -400,6 +400,11 @@
         devstack_plugins:
           tacker: https://opendev.org/openstack/tacker
         tox_envlist: dsvm-functional-sol-kubernetes
+        devstack_local_conf:
+          post-config:
+            $TACKER_CONF:
+              kubernetes_vim:
+                stack_retries: 110
       controller-k8s:
         devstack_local_conf: {}
         devstack_plugins: