This reverts commit 3f91f4b2.

Bug 1745

Updates of existing bluegene advanced reservations did not work at all.
Some multi-core configurations resulting in an abort due to creating
  core_bitmaps for the reservation that only had one bit per node rather
  than one bit per core.
These bugs were introduced in commit 5f258072

Logic was assuming the reservation had a node bitmap which was
  being used to check for overlapping jobs. If there is no node
  bitmap (e.g. a licenses only reservation), an abort would result.

Bug 1739

Bug 1743

Bug 1733

1. I submit a first job that uses 1 GPU:
$ srun --gres gpu:1 --pty bash
$ echo $CUDA_VISIBLE_DEVICES
0

2. while the first one is still running, a 2-GPU job asking for 1 task per node
waits (and I don't really understand why):
$ srun --ntasks-per-node=1 --gres=gpu:2 --pty bash
srun: job 2390816 queued and waiting for resources

3. whereas a 2-GPU job requesting 1 core per socket (so just 1 socket) actually
gets GPUs allocated from two different sockets!
$ srun -n 1  --cores-per-socket=1 --gres=gpu:2 -p testk --pty bash
$ echo $CUDA_VISIBLE_DEVICES
1,2

With this change #2 works the same way as #3.
bug 1725

Only going to do this in the master as it may affect scripts.

This reverts commit 454f78e6.

Conflicts:
	NEWS

switch/cray: Refine logic to set PMI_CRAY_NO_SMP_ENV environment variable.
Rather than testing for the task distribution option, test the actual
task IDs to see fi they are monotonically increasing across all nodes.
Based upon idea from Brian Gilmer (Cray).

afterward cause a divide by zero error.

corruption if thread uses the pointer basing validity off the id.

Bug 1710

Bug 1495

Correct count of CPUs allocated to job on system with hyperthreads.
The bug was introduced in commit a6d3074d
On a system with hyperthreads:
srun -n1 --ntasks-per-core=1 hostname
you would get:
slurmctld: error: job_update_cpu_cnt: cpu_cnt underflow on job_id 67072

preempt/job_prio plugin: Implement the concept of Warm-up Time here. Use
the QoS GraceTime as the amount of time to wait before preempting.
Basically, skip preemption if your time is not up.

a job runs past it's time limit.

Bug 1705

However, --mem=0 now reflects the appropriate amount of memory in the
system, --mem-per-cpu=0 hasn't changed.  This allows all the memory to
be allocated in a cgroup but is not "consumed" and is available for
other jobs running on the same host.
Eric Martin, Washington University School of Medicine

Correct list of unavailable nodes reported in a job's "reason" field when
that job can not start.
bug 1614

bug 1679

Bug 1679

switch/cray: Revert logic added to 14.11.6 that set "PMI_CRAY_NO_SMP_ENV=1"
if CR_PACK_NODES is configured.
bug 1585

preempt/job_prio plugin: Implement the concept of Warm-up Time here. Use
the QoS GraceTime as the amount of time to wait before preempting.
Basically, skip preemption if your time is not up.