Set job with Java persister non-voting

Java implementation of persister has been deprecated and will not be
further developed. This change sets the CI job testing the Java
persister as non-voting to avoid blocking merging new Python code.

The job is still been run for support legacy deployments.

Change-Id: I39fefaf4eb8cb1310d574e2aa805ac618e700541
Story: 2005628
Task: 36761

.zuul.yaml

@@ -119,6 +119,7 @@
 - job:
     name: monasca-tempest-python2-java-cassandra
     parent: monasca-tempest-base
+    voting: false
     vars:
       devstack_localrc:
         USE_PYTHON3: false
@@ -163,7 +164,6 @@
         - monasca-tempest-python2-influxdb
         - monasca-tempest-python3-influxdb
         - monasca-tempest-python2-cassandra
-        - monasca-tempest-python2-java-cassandra
         - monascalog-python3-tempest
     post:
       jobs: