Correct the slurm.conf man pages and checkpoint_blcr.html page
describing that jobs must be drained from cluster before deploying
any checkpoint plugin.
Fix issue where if using munge and munge wasn't running and a slurmd
needed to forward a message the slurmd would core dump.
Just a little sanity check after a free.
Merge remote-tracking branch 'origin/slurm-2.6'

Conflicts:
	doc/man/man5/slurm.conf.5