MAX_SERVER_THREADS is exceeded. Thread counter, mutex, and cond
logic all moved into new allocate/deallocate server thread functions.

assumes control. It previously captured state only when the backup
controller daemon was initiated.

This was not happening for the backup slurmctld.

   setting SLURM_NODELIST in the environment)

in slurmd killing itself if the KILL_JOB RPC arrived before the job began
execution (the pid in the data structure was still zero.

cases. Exit code is now 0 only if all commands execute without error.
Exit code is 1 if any failure occurs for any command executed.
(gnats:278)

when the job does not exist).

it is a duplicate record.

 o check for a job step state of STARTED before issuing kill_job rpc

was only going to 65500 for the job_id and the step_id was always zero.
This change does not elimiate the possibility of an error, but reduces
its probability by a factor of about 65000.
(gnats:276)

to job_kill request and slurmctld leaves node and job in COMPLETING state
until the slurmd issues an EPILOG_COMPLETE RPC on each node. This permits
better support for non-killable processes and/or long-running epilog scripts.
Several minor changes in node registration handling and slurmctld agent
logic to better address a flood of incomming RPC (typically when system
restarts).
(gnats:268)

gnats slurm/270.

   may result in multiple executions of system epilog for a single job
   (gnats:267)

of socket communications. Previously was sometimes overwriting legitimate
SLURM error code with fcntl error code of EINTR.

sort of slurm error.

on a job kill. Let the KILL_JOB RPC do all of the cleanup. This removes
a redundant RPC. - Moe