Adding octavia_provider_network_mtu-parameter parameter

The `octavia_provider_network_mtu-parameter` defaults to 1500
to not accidentially use `global_physnet_mtu` on deployment with
large MTU settings

Change-Id: I9fa33c5ee76197191f1e66b7a70a4c1c0a5fa394

releasenotes/notes/octavia_provider_network_mtu-parameter-62978008dfe0882e.yaml

@@ -0,0 +1,17 @@
+---
+features:
+  - |
+    A new parameter `octavia_provider_network_mtu` is added to set the
+    MTU to 1500 by default. This is important for deployments which
+    allow jumbo frames while setting the management to the standard
+    Ethernet MTU. The MTU can be still changed at any point during the
+    initial octavia deployment or with the
+    `openstack network set --mtu` command line.
+upgrade:
+  - |
+    A new parameter `octavia_provider_network_mtu` is added to set the
+    MTU to 1500 by default. This is important for deployments which
+    allow jumbo frames while setting the management to the standard
+    Ethernet MTU. The MTU can be still changed at any point during the
+    initial octavia deployment or with the
+    `openstack network set --mtu` command line.

tasks/octavia_mgmt_network.yml

@@ -39,6 +39,7 @@
         provider_network_type: "{{ octavia_provider_network_type }}"
         provider_physical_network: "{{ octavia_provider_network_name }}"
         provider_segmentation_id: "{{ octavia_provider_segmentation_id | default(omit) }}"
+        mtu_size: "{{ octavia_provider_network_mtu | default('1500') }}"
         interface: admin
         verify: "{{ not keystone_service_adminuri_insecure }}"
       register: add_network