Release 2.5.22

Issues fixed

Cancelling a pending job now reliably cancels it (ticket: 4641)
Previously, cancelling a job while it was still pending — queued because the maximum number of concurrent jobs had been reached — did not reliably stop it. When a concurrency slot later became free, the cancelled job would start executing anyway and could display a negative elapsed time. Cancelling a pending job now reliably cancels it and it will not start afterwards.