acctg-freq is a string instead of a uint16_t

common.

If set, the job's size component will be based upon not the job size
alone, but the job's size divided by it's time limit.

Conflicts:
	NEWS
	src/slurmctld/controller.c
	src/slurmctld/job_scheduler.c

The problem we have observed is the backfill scheduler temporarily
gives up its locks (one second), but then reclaims them before the
backlog of work completes, basically keeping the backfill scheduler
running for a really long time when under a heavy load.
bug 297

Fix minor bug in sdiag backfill scheduling time reported on Bluegene systems
Improve explanation of backfill scheduling cycle time calculation.

Defers (rather than forgets) reboot request with job running on the
node within a reservation.

Fix minor bug in sdiag backfill scheduling time reported on Bluegene systems
Improve explanation of backfill scheduling cycle time calculation.

Defers (rather than forgets) reboot request with job running on the
node within a reservation.