Fix downstream/upstream mirror triggering

Change-Id: If7efdc5961cec439502cf780ab45e00da237330d
diff --git a/jenkins/client/job/git-mirrors/downstream/init.yml b/jenkins/client/job/git-mirrors/downstream/init.yml
index 9333e6a..0ddc0ce 100644
--- a/jenkins/client/job/git-mirrors/downstream/init.yml
+++ b/jenkins/client/job/git-mirrors/downstream/init.yml
@@ -1,6 +1,7 @@
 parameters:
   _param:
     jenkins_git_mirror_downstream_jobs: []
+    jenkins_pollscm_spec: "H/60 * * * *"
   jenkins:
     client:
       job_template:
@@ -21,18 +22,8 @@
               credentials: "gerrit"
               script: git-mirror-pipeline.groovy
             trigger:
-              gerrit:
-                project:
-                  "{{downstream}}":
-                    branches:
-                      - master
-                message:
-                  build_successful: "Build successful"
-                  build_unstable: "Build unstable"
-                  build_failure: "Build failed"
-                event:
-                  ref:
-                    - updated
+              pollscm:
+                spec: ${_param:jenkins_pollscm_spec}
             param:
               SOURCE_URL:
                 type: string