no change in logic

many env vars were not being set since rev 20268

BLUEGENE - Removed thread pool for destroying blocks.  It turns out the memory leak we were concerned about for creating and destroying threads in a plugin doesn't exist anymore.  This increases throughput dramatically, allowing multiple jobs to start at the same time.

    invalid features: "Job 65537 has invalid feature list: fat".

    have been removed or replaced since version 2.0 or earlier: HashBase,
    HeartbeatInterval, JobAcctFrequency, JobAcctLogFile (instead use
    AccountingStorageLoc), JobAcctType, KillTree, MaxMemPerTask, and
    MpichGmDirectSupport.

    many jobs on queue should be tested for attempted scheduling when a job
    completes or other routine events. Default value is 100 jobs. The full job
    queue is tested on a less frequent basis. This option can dramatically
    improve performance on systems with thousands of queued jobs.

   error is encountered instead of continuing with more job updates.

Fix timout logic in sched/backfill
Modify calls to schedule() to add maximum queue depth, which speeds up the rate at
which jobs can be submitted dramatically. The Full depth is tested by the backfill
scheduler and periodically in slurmctld_background(), only 100 jobs are tested at
the time of each job submit or completion.

    minimize system fragmentation.

Update docs and fix minor bug in step gpu gres env var

More testing is needed, but basic functionality is now available!!!