Handle unexpectedly large lines for hostlists. (Bug 2333.)

While here rework to avoid extraneous xstrcat calls by using
xstrfmtcat instead of snprintf + xstrcat. Collapse line end into
own string for readability.

No performance or functional change, aside from removing possible
line truncation (which will silence additional Coverity warnings).

Removes a double xfree() in slurm_sprint_reservation_info().

When a reservation is created or updated, compress user provided node names
    using hostlist functions (e.g. translate user input of "Nodes=tux1,tux2"
    into "Nodes=tux[1-2]").
bug 2333

Reported by CLANG
Continuation of 7eff526c

Match behavior of other PBS-like resource managers. Bug 2330.

using TRES as a key word.

statements.

Don't allow user specified reservation names to disrupt the normal
    reservation sequeuece numbering scheme.
bug 2318

anything.  The slurmd will process things correctly after the fact.

The restriction from Cray has been lifted.
bug 2317

Otherwise upgrading slurm on a compute node while tasks are running
will cause plugin mismatch, as slurmstepd would not load the library
until task completion before. Bug 2319.

Conflicts:
	src/slurmctld/job_scheduler.c

Bug 2314.

this happens anywhere in the code but just incase it ever does, lets fix
it.

Continuation of fa331e30.

This can be caused by a core reservation on nodes which get taken
  out of the system or fail.
bug 2296

salloc/sbatch/srun did not mention this. Also reference OverTimeLimit
as another option affecting the final run time. Bug 2309.

the job starts update the cpus_per_task appropriately.

This also moves update num_tasks to after the setting of node counts on
an update.  It didn't appear to matter, but the cpus_per_task and
pn_min_cpus had to be figured out after the cpus and nodes were set but
before tasks.

Bug 2302

burst_buffer/cray - Improve tracking of allocated resources to handle race
    condition when reading state while buffer allocation is in progress.
Also initialize a mutex

DBD for the first time.  The corruption is only noticed at shutdown.

Bug 2293

Conflicts:
	META
	NEWS
	src/slurmctld/job_scheduler.c

Set job's reason to "Priority" when higher priority job in that partition
    (or reservation) can not start rather than leaving the reason set to
    "Resources".
bug 2285

error message.

If a reservation's nodes value is "all" then track the current nodes in the
    system, even if those nodes change. Nodes will automatically be added to
    or removed from a reservation when slurm.conf changes.
bug 2204

Bug 2281

Rename the variable to match rest of codebase while here. This is related to
bug 2295, although snprintf() protects against buffer overflow in 15.08 and up.

Later releases have switched over to snprintf to avoid this issue, but 14.11
did not get that patch. Bug 2295.