set neutron mtu to match system mtu

Neutron config needs to be updated to match the system
mtu setting.

Depends-On: Iedd4cfbb0e1c9471cb1ae53b8b6acc266273463f
Change-Id: I966628caead41447641984e1f25741b873863d76

toci-quickstart/config/testenv/ovb.yml

@@ -47,6 +47,8 @@ host_network_interfaces:
   - eth1
   - "{% if network_isolation|default(true)|bool %}eth2{% endif %}"
 mtu_interface: "{{ host_network_interfaces|select()|list }}"
+undercloud_local_mtu: 1350
+overcloud_neutron_global_physnet_mtu: 1350
 floating_ip_cidr: >-
   {%- if network_isolation|default(true)|bool %}10.0.0.0/24
   {%- else %}192.168.24.0/24