If a job is deleted and then GetJobs API is immediately called,
it is possible for a job to be returned in the response. This is likely
due to the GetJobs API being executed on a node with a slightly
stale cluster state which shows the job as still existing.
So we delegate to the master node so the list of jobs/tasks is current.
After routing to the master, we need to check if the rollup job
is in the PersistentTask's CS. A job can be acknowledged canceled,
removed from the CS, but the allocated task is still alive. So we
first check the CS to make sure it's really there before going to the
allocated task to get the status.
As extra precaution, when running local to the task, we also make
sure the task isn't canceled before including it in the response.
relates elastic/x-pack-elasticsearch#4041
Original commit: elastic/x-pack-elasticsearch@3b6fb65e12
e8a6c9f5d1