Plug memory leak associated with successful replacement of failing node.

on allocation failure, prevent skipping over xfree of strings.

And add missing documenation.
Bug 1921

GRES were not being properly tracks for multiple simultaneous steps.
A step which could have run later could be rejected as never being
able to run.
Replacement for commit dd842d79, which was reverted in commit 6f73812875c
bug 1925

That commit would address a limited subset of problems and introduce
other bugs rather than fixing the root of the problem.

and you use all the GRES up instead of reporting the configuration isn't
available you hold the requesting step until the GRES is available.

Don't trucate task ID information in "squeue --array/-r" output.
Task ID info in sview also expanded to 64 characters (from ~16 chars).

Fix for bad cut and paste.  Looks like the original code was just a copy
of the access parsing.

last_time would be uninitialized.

    slurmctld.

Use more flexible mechnanism to find json installation.

Fix srun from inheriting the SLURM_CPU_BIND and SLURM_MEM_BIND environment variables when running in an existing srun (e.g. an srun within an salloc).

Bug 1888