Increase the max_request_body_size in tempest runs

Older stable branches have the tempest and tempest plugin pinned to a specific
version which doesn't have test fix for the limited request body size default.
This patch will set a 10x max_request_body_size for oslo middleware sizelimit,
which should be enough for the tests to run.

Change-Id: I937f1ebc6554f93034fb261cf3090f623c150b90

Author: johnsom

.zuul.yaml

@@ -6,6 +6,13 @@
         DESIGNATE_SERVICE_PORT_DNS: 5322
         TEMPEST_PLUGINS: /opt/stack/designate-tempest-plugin
         USE_PYTHON3: true
+      devstack_local_conf:
+        post-config:
+          $DESIGNATE_CONF:
+            oslo_middleware:
+              # Make this larger than the defaults for the tempest tests
+              # on pinned releases
+              max_request_body_size: 1146880
       devstack_plugins:
         designate: https://opendev.org/openstack/designate
       devstack_services: