enabling ironic reconfigures physnet1 as vlan and all as flat

[Radosław Piliszek]

Undocumented "feature" of enable_ironic is that it makes physnet1 a vlan network instead of flat and allows any network ("*") as flat.

excerpt from ml2_conf.ini.j2
https://opendev.org/openstack/kolla-ansible/src/commit/7c17c3c45e3abee40a3ce1d2fc98b313b020ca30/ansible/roles/neutron/templates/ml2_conf.ini.j2#L36-L48

  [ml2_type_vlan]
  {% if enable_ironic | bool %}
  network_vlan_ranges = physnet1
  {% else %}
  network_vlan_ranges =
  {% endif %}

  [ml2_type_flat]
  {% if enable_ironic | bool %}
  flat_networks = *
  {% else %}
  flat_networks = {% for bridge in neutron_bridge_name.split(',') %}physnet{{ loop.index0 + 1 }}{% if not loop.last %},{% endif %}{% endfor %}
  {% endif %}