Add ZUUL_VOTING parameter

So that jobs, but especially post-processing such as elastic-recheck,
can tell whether Zuul considers a job voting or not.

Change-Id: I40746bb77aab900c1dd2637f940c14f72a904a61
diff --git a/tests/test_scheduler.py b/tests/test_scheduler.py
index 61a2d09..4955de6 100755
--- a/tests/test_scheduler.py
+++ b/tests/test_scheduler.py
@@ -111,6 +111,9 @@
         self.assertReportedStat(
             'zuul.pipeline.gate.org.project.total_changes', value='1|c')
 
+        for build in self.builds:
+            self.assertEqual(build.parameters['ZUUL_VOTING'], '1')
+
     def test_initial_pipeline_gauges(self):
         "Test that each pipeline reported its length on start"
         pipeline_names = self.sched.layout.pipelines.keys()
@@ -1256,6 +1259,9 @@
             self.getJobFromHistory('nonvoting-project-test2').result,
             'FAILURE')
 
+        for build in self.builds:
+            self.assertEqual(build.parameters['ZUUL_VOTING'], '0')
+
     def test_check_queue_success(self):
         "Test successful check queue jobs."