Add Octavia Tempest Plugin

Octavia Tempest Plugin is required to call Octavia API on Kuryr-
Tempest-Plugin.

Change-Id: If00c3af9ee8689f05eecf5370758edb50775d381

.zuul.d/base.yaml

@@ -40,13 +40,14 @@
       tox_envlist: 'all'
       network_api_extensions_common:
         - tag-ports-during-bulk-creation
+      tempest_plugins:
+        - kuryr-tempest-plugin
       devstack_localrc:
         Q_AGENT: openvswitch
         Q_ML2_TENANT_NETWORK_TYPE: vxlan
         Q_ML2_PLUGIN_MECHANISM_DRIVERS: openvswitch,linuxbridge
         ML2_L3_PLUGIN: router
         KURYR_K8S_API_PORT: 6443
-        TEMPEST_PLUGINS: '/opt/stack/kuryr-tempest-plugin'
         KURYR_K8S_CLOUD_PROVIDER: false
         ETCD_USE_RAMDISK: true
         USE_PYTHON3: true

.zuul.d/octavia.yaml

@@ -20,12 +20,17 @@
     required-projects:
       - openstack/octavia
       - openstack/python-octaviaclient
+      - openstack/octavia-tempest-plugin
     pre-run: playbooks/get_amphora_tarball.yaml
     host-vars:
       controller:
         devstack_plugins:
           octavia: https://opendev.org/openstack/octavia
+          octavia-tempest-plugin: https://opendev.org/openstack/octavia-tempest-plugin.git
     vars:
+      tempest_plugins:
+        - kuryr-tempest-plugin
+        - octavia-tempest-plugin
       devstack_localrc:
         OCTAVIA_AMP_IMAGE_FILE: "/tmp/test-only-amphora-x64-haproxy-ubuntu-bionic.qcow2"
         OCTAVIA_AMP_IMAGE_SIZE: 3