BurstBuffer/cray: Fix job record purging if cancelled from pending state.
The problem can occur when the a burst buffer record was created for
the job in the plugin data structure, but no burst buffers were actually
allocated for it.
bug 2165

BurstBuffer/cray: Enable clearing of burst buffer string on completed job
    as a means of recovering from a failure mode.
Format is "scontrol update jobid=### burstbuffer=".
partial resolution of bug 2165

bug 2028

BurstBuffer/cray: Add logic to terminate dw_wlm_cli child processes at
    shutdown.
bug 2166

Previous logic required the buffer name to work
bug 2167

Added srun option of --bcast to move executable file to compute nodes

burst_buffer/cray: Support file staging when job lacks job-specific buffer
    (i.e. only persistent burst buffers).
bug 2113

bug 2143

Backfill scheduler: Test association and QOS node limits before reserving
    resources for pending job.
bug 2129

Prevents the following sequence from causing a segfault:
$ scontrol create partitionname=stuff nodes=ALL
$ sbatch --wrap="hostname" -o/dev/null -p stuff
Submitted batch job 1047468
$ scontrol delete partitionname=stuff
$ scontrol update jobid=1047468 partition=stuff

tree.

Bug 2006

step.

Stop searching sbatch scripts for #PBS directives after 100 lines of
    non-comments. Stop parsing #PBS or #SLURM directives after 1024 characters
    into a line. Required for decent perforamnce with huge scripts.

Previously only supported by SlurmUser and root.

Previously only reserved space for one task of pending job array.

Support taking node out of FUTURE state with "scontrol reconfig" command.
Previous logic would keep node in FUTURE state if that was the original
configuration when slurmctld started. If job was running on the node,
it will stay running, but the node make not be visible.

Previous logic would create a environment and script file for each
  task of a job array (hard link to original actually). Due to
  file system limitations and clutter, this was less than ideal.
  This patch eliminates the redundant files, using only the original
  file created for the job array. This should also make support for
  burst buffers easier in the future for job arrays.

Make SLURM_ARRAY_TASK_MIN, SLURM_ARRAY_TASK_MAX, and SLURM_ARRAY_TASK_STEP
    environment variables available to PrologSlurmctld and EpilogSlurmctld.

We needed to send a finish from each node in the step whether it had
any activity or not.  This way the controller knew things were done
on the node and the data was sent to the database.

Bug 2097

Burst_buffer/cray: Don't stall scheduling of other jobs while a stage-in
    is in progress.
bug 2114

Fix to purge terminated jobs with burst buffer errors.
bug 2123

The prolog_running counter can now exceed 1. New logic raises limit
from 1 to 4 before preventing job recovery on restart.