A test fix for the thread cancellation routine.

A test fix for the thread cancellation routine.
We only log situations where we would have cancelled a thread, we don't
actually cancel them.
With this code we should not see cancellation requests during normal
running.
Cancelation requests during normal running were due to threads being
asked to stop when load decreased but the idle thread detection aloud a
thread to be asked to stop just as select gave it a task and made it not
idle.
Now if select gives a thread a job to do and the thread was asked to
stop during the select the thread changes its state back to running and
refuses the stop request. This only happens if the system is NOT
shutting down.