bug 306 fix

Handy if you want to test the IMPI energy plugin but your ipmi doesn't
work with power.

EnergyIPMIVariable=Temp

Is the only thing accepted currently

and extra function

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