Remove timer trigger for git mirror sync jobs

Change-Id: Id06eda7cdc6e1973b747b64d3029a696b4b4b659
Related-prod: #PROD-29757 (PROD:29757)
              #PROD-29421 (PROD:29421)
(cherry-picked from f2699fb4ec2215318389ba599445a0b866144994)
diff --git a/jenkins/client/job/git-mirrors/downstream/init.yml b/jenkins/client/job/git-mirrors/downstream/init.yml
index 8803f18..fbfcd56 100644
--- a/jenkins/client/job/git-mirrors/downstream/init.yml
+++ b/jenkins/client/job/git-mirrors/downstream/init.yml
@@ -1,7 +1,6 @@
 parameters:
   _param:
     jenkins_git_mirror_downstream_jobs: []
-    jenkins_pollscm_spec: "H/60 * * * *"
   jenkins:
     client:
       job_template:
@@ -22,9 +21,6 @@
               branch: "${_param:jenkins_pipelines_branch}"
               credentials: "gerrit"
               script: git-mirror-pipeline.groovy
-            trigger:
-              pollscm:
-                spec: ${_param:jenkins_pollscm_spec}
             param:
               SOURCE_URL:
                 type: string