Cleanup the config file on ./clean.sh

When users unstack and clean on devstack, the old config files
should be removed to avoid potential issues. As a result, users
will get a fresh new install on the next ./stack.sh

Change-Id: I4c63ca1b6101a9f08bf9629b2bd7384b2198dac5

devstack/lib/zun

@@ -102,6 +102,7 @@ function cleanup_zun {
     fi
 
     remove_uwsgi_config "$ZUN_UWSGI_CONF" "$ZUN_UWSGI"
+    sudo rm -rf $ZUN_CONF_DIR
 }
 
 # configure_zun() - Set config files, create data dirs, etc