deploy issues with ExternalNetCidr

gistfile1.txt

--- deploy.sh ---

#!/bin/bash

openstack overcloud deploy --templates \
        -r /home/stack/templates/roles_data.yaml \
        -e /home/stack/templates/overcloud_images.yaml \
        -e /home/stack/templates/node-info.yaml \
        -e /home/stack/openstack-tripleo-heat-templates-rendered/environments/ceph-ansible/ceph-ansible.yaml \
        -e /home/stack/templates/ceph-config.yaml \
        -n /home/stack/templates/network_data.yaml \
        -e /home/stack/openstack-tripleo-heat-templates-rendered/environments/network-isolation.yaml \
        -e /home/stack/openstack-tripleo-heat-templates-rendered/environments/network-environment.yaml \
        -e /home/stack/openstack-tripleo-heat-templates-rendered/environments/net-bond-with-vlans.yaml \
        -e /home/stack/templates/custom-network-configuration.yaml \
        --ntp-server foo.com

--- ~/templates/network_data.yaml ---

- name: External
  vip: true
  name_lower: external
  vlan: 77
  ip_subnet: '10.237.77.0/24'
  allocation_pools: [{'start': '10.237.77.4', 'end': '10.237.77.250'}]
  gateway_ip: '10.237.77.1'
  ipv6_subnet: '2001:db8:fd00:1000::/64'
  ipv6_allocation_pools: [{'start': '2001:db8:fd00:1000::10', 'end': '2001:db8:fd00:1000:ffff:ffff:ffff:fffe'}]
  gateway_ipv6: '2001:db8:fd00:1000::1'

--- network-environment.yaml (the only modified part) ---

parameter_defaults:
  <snip>
  ExternalNetCidr: '10.237.77.0/24'
  ExternalAllocationPools: [{'start': '10.237.77.4', 'end': '10.237.77.250'}]
  ExternalInterfaceDefaultRoute: '10.237.77.1'
  <snip>