[Ussuri only] Make tripleo jobs non-voting temporarily

Unfortunately tripleo-standalone job in stable/usssuri is still broken,
so let's make it non-voting temporarily so that all ussuri work in
puppet can be done until tripleo job is actually fixed.

NOTE:
This patch should be reverted once tripleo-standalone job in
stable/ussuri is fixed.

Change-Id: Ic047b2be49cd66adc156b3f728cf9c3afe4ddffe

zuul.d/tripleo.yaml

@@ -42,11 +42,13 @@
       - ^.gitignore$
       - ^setup.cfg$
       - ^setup.py$
+    voting: false
 
 - job:
     name: tripleo-puppet-ci-centos-8-standalone
     parent: tripleo-ci-centos-8-standalone
     irrelevant-files: *standalone_irrelevant_files
+    voting: false
 
 - project-template:
     name: tripleo-puppet-standalone