2955: Periodically compare Job.running to @running and fail any jobs not in
@running.
2955: Fixed refresh_running to set finished_at on failed jobs.  Increased
polling period to 30 seconds.
2955: Added check that an orphan job hasn't produces any logs for 5 minutes
before automatically failing it.  arv-run-pipeline-instance will identify jobs
that are running=false and success=false as failed even if finished_at is null.
2955: crunch-dispatch now sends a clean environment to crunch-job. (cherry-picked from #2882)

Conflicts:
	services/api/script/crunch-dispatch.rb
2955: Fixed query of log table that checks for age of last log by an orphan
job.
2955: Sets jobrecord.canceled_at when canceling/failing an orphan job.
arv-run-pipeline-instance recognizes canceled jobs when counting the number of ended jobs.
2955: Moved logic to clean jobs table from crunch-dispatch into a standalone
script.
2955: Renamed script to "cancel_stale_jobs".  Fixed spelling canceled_at -> cancelled_at.
Merge branch 'master' into 2955-fail-orphan-jobs
Reverted change a0aba6d "crunch-dispatch now sends a clean environment to crunch-job"
Merge branch '2955-fail-orphan-jobs' closes #2955