ironic: Set MTU on provisioning and cleaning Neutron networks

Previously we were not applying an MTU defined in Kayobe networks.yml to
the provisioning and cleaning networks in Neutron. This could lead to
issues when nodes communicate with the Ironic and Inspector APIs.

Change-Id: Id9418e4e88c52056412daa22462aa611bfcc59ae

ansible/provision-net.yml

@@ -18,6 +18,7 @@
     venv: "{{ virtualenv_path }}/openstacksdk"
     provision_net:
       name: "{{ kolla_ironic_provisioning_network }}"
+      mtu: "{{ provision_wl_net_name | net_mtu | default(omit, True) }}"
       provider_network_type: "{% if provision_wl_net_name | net_vlan %}vlan{% else %}flat{% endif %}"
       provider_physical_network: "{{ provision_wl_net_name | net_physical_network | default('physnet1', True) }}"
       provider_segmentation_id: "{{ provision_wl_net_name | net_vlan }}"
@@ -31,6 +32,7 @@
           allocation_pool_end: "{{ provision_wl_net_name | net_neutron_allocation_pool_end }}"
     cleaning_net:
       name: "{{ kolla_ironic_cleaning_network }}"
+      mtu: "{{ cleaning_net_name | net_mtu | default(omit, True) }}"
       provider_network_type: "{% if cleaning_net_name | net_vlan %}vlan{% else %}flat{% endif %}"
       provider_physical_network: "{{ cleaning_net_name | net_physical_network | default('physnet1', True) }}"
       provider_segmentation_id: "{{ cleaning_net_name | net_vlan }}"

releasenotes/notes/provision-net-mtu-befdda04224f49a6.yaml

+---
+fixes:
+  - |
+    Fixes an issue where the MTU defined in Kayobe was not applied to Ironic
+    provisioning and cleaning networks in Neutron.