This patch abstracts the establishment of slurm user credentials
in slurmctld when SlurmUser != root. It adds a call to setgid()
to adopt the SLURM user's primary group, instead of running with
whatever primary group was in effect when invoking the slurmctld
executable. Also, errors in establishing user credentials are
fatal errors, instead of just warnings.

This is a minor security enhancement.

    --cpus-per-task option not properly handled.

We actually want to preserve the set_oomadj() function in slurm v1.4, but
have removed it completely from v1.3.

  the values of SLURMD_OOM_ADJ and SLURMSTEPD_OOM_ADJ environment
  variables. This can be used to prevent daemons being killed when
  a node's memory is exhausted.

Plus some cosmetic work. Logic is somewhat different in v1.4 and v1.3.

    specifying a non-stardard slurmstepd file, used  for testing purposes.

    communications in greater detail.

    than the ThreadsPerCore (invalid memory reference).

scripts per request from Jerry Smith (SNL)

    BLCR. Patch from Hongjia Cao, NUDT, China.
svn merge -r16811:16866 https://eris.llnl.gov/svn/slurm/branches/blcr

    slurmctld daemon).

    allocation with respect to network topology.
svn merge -r16770:16795 https://eris.llnl.gov/svn/slurm/branches/topology

    re-launch a job step if the step fails with a reserved port conflict.

    as any task of a job step exits with a non-zero exit code. Patch based
    on work from Eric Lin, Bull.

    interval between executions of the backfill scheduler logic.