Add designate-manage pool scenario tests

So far we did not test designate-manage pool commands with real end-user
scenarios.

This patch adds designate-manage pool scenario tests.

Change-Id: Iaf848350a502b8f1697b495ee645a09a00974f24
diff --git a/devstack/plugin.sh b/devstack/plugin.sh
index 288117e..3a0cee2 100644
--- a/devstack/plugin.sh
+++ b/devstack/plugin.sh
@@ -12,6 +12,10 @@
     if [ -n "$DESIGNATE_BIN_DIR" ]; then
         iniset $TEMPEST_CONFIG dns_feature_enabled designate_manage_path ${DESIGNATE_BIN_DIR}/designate-manage
     fi
+
+    POOLS_YAML_PATH=/etc/designate/multiple-pools.yaml
+    cp /etc/designate/pools.yaml ${POOLS_YAML_PATH}
+    sed -i 's/"pool_level": "secondary"/"pool_level": "tertiary"/' ${POOLS_YAML_PATH}
 }
 
 if [[ "$1" == "stack" ]]; then