Run only Octavia smoke tests in periodic scenario010 job

Similar change was done in u/s CI some time ago as it seems that running
all Octavia scenario tests takes too much time and job is timing out.

Change-Id: I3c7b0eb1a2c4aab67c38b8fe2c3039c60b66fa69

zuul.d/standalone-jobs.yaml

@@ -343,6 +343,8 @@
         standalone_environment_files:
           - 'environments/low-memory-usage.yaml'
           - 'ci/environments/scenario010-standalone.yaml'
+        tempest_test_whitelist:
+          - '^octavia_tempest_plugin.*smoke'
 
 - job:
     name: periodic-tripleo-ci-centos-8-scenario010-kvm-standalone-master