Fix permission for mounted director kubernetes#2260

Work-around for kubernetes#2260 until the underlying problem is addressed (kubernetes/kubernetes#2630 - though not 100%).

docs/tutorials/stateful-application/basic-stateful-set.md

@@ -278,7 +278,7 @@ Write the Pods' hostnames to their `index.html` files and verify that the NGINX
 webservers serve the hostnames.
 
 ```shell
-for i in 0 1; do kubectl exec web-$i -- sh -c 'echo $(hostname) > /usr/share/nginx/html/index.html'; done
+for i in 0 1; do kubectl exec web-$i -- sh -c 'echo $(hostname) > /usr/share/nginx/html/index.html && chmod 755 /usr/share/nginx/html'; done
 
 for i in 0 1; do kubectl exec -it web-$i -- curl localhost; done
 web-0