Fix for handling node registration messages from older versions without
energy data.
IMPI - move thread launcher to it's own thread and make it's threads
able to be canceled.  In older versions of freeimpi some of the calls
(ipmi_monitoring_sensor_readings_by_record_id) could hang if it doesn't
work correctly and the timeout mech appears to cause memory corruption.

The code now handles this and does the right thing.
Merge remote-tracking branch 'origin/slurm-2.5'

Conflicts:
	src/slurmctld/node_mgr.c