help to eliminate the creation of srun core files.

It should never have been added.

Normalized the way pidfile are created by the slurm daemons.  With extra documentation for better understanding of when to call the create_pidfile function.

    sbatch, and srun commands to work properly with a suffix of "MB", "GB",
    etc. and not only with a single letter (e.g. "M", "G", etc.).

    allocations created using srun (not just sbatch).

    that user ID. Patch from Hongjia Cao, NUDT.

    backfill scheduling while a job is completing. Patch from Gerrit Renker,
    CSCS.

Fix issue with associations attached to a specific partition with no other association, and requesting a different partition.

Fixed issue where assoc_mgr cache wasn't always loaded correctly if the slurmdbd wasn't running when the slurmctld was started.

Fixed issue where if a system has unset messages to the dbd in 2.1 and upgrades to 2.2.  Messages are now processed correctly now.

    minimize lost messages. Effects slurmd epilog complete messages and PMI
    key-pair transmissions. Patch from Gerrit Renker, CSCS.