upgrade jenkins.ovirt.org to latest LTS version

Job 1278 was running for 54 minutes when I cancelled it. It was stuck after "Collecting mock logs" which is where the pipeline plugin should take over immediately (this can be seen in the re-triggered job 1279). Maybe it's a pipeline bug, not sure - need to see if this reproduces on Staging so that we can troubleshoot.

Actually its kins of dangerous to tyr to abort these jobs in the middle, because it might leave Lago VMs and files laying around on the slave.

Since a typical run of this just is ~40m, waiting 10m for it is not long...

Indeed, I had to cancel the job because it just stuck once I set Jenkins into "prepare for shutdown" mode for some reason. I tried to let it finish by cancelling the "prepare for shutdown" mode yet it didn't do anything for 10 minutes. I was unsure about which of the change queue jobs can be triggered manually but will now for future as we'll probably hit similar scenarios on next upgrades.

I see that change-queue tester job was aborted last night. I guess that was in order to run the upgrade.

Next time, if you abort the tester job please re-run it when Jenkins is back up. It was in the middle of a bisection loop last night and it just waited until somebody sent a new patch this morning to resume, which is a shame because we could've had results by now.

Production instance updated.

Notes from the upgrade:
1) core update no longer runs "chown" so the process no longer takes an hour to complete
2) there's a warning during startup that may need investigation (it may have existed before this upgrade):
WARNING: Build record migration (https://jenkins.io/redirect/build-record-migration) is one-way. If you need to downgrade Jenkins, run: java -classpath "/var/cache/jenkins/war/WEB-INF/lib/jenkins-core-2.60.1.jar:/var/cache/jenkins/war/WEB-INF/lib/commons-io-2.4.jar:/var/cache/jenkins/war/WEB-INF/lib/stapler-1.250.jar:/var/cache/jenkins/war/WEB-INF/lib/ant-1.8.4.jar:/var/cache/jenkins/war/WEB-INF/lib/commons-lang-2.6.jar" jenkins.model.RunIdMigrator "/var/lib/data/jenkins"