Adjust Jenkinsfile for move of releng.aggregator to github

Change-Id: Ib68f85e6407fc71d30645825ec2809e95d6f1c42
Reviewed-on: https://git.eclipse.org/r/c/platform/eclipse.platform/+/190624
Tested-by: Platform Bot <platform-bot@eclipse.org>
Reviewed-by: Alexander Kurtakov <akurtako@redhat.com>
1 file changed