typo fix; per-script number of reducers

Fixed a typo in healthreportutils.py.

Added the ability to set a custom number of reducers by defining a function "num_reduce_tasks" in your script. Ex:
def num_reduce_tasks():
    return 23
There may be a better way to do this; I copied the approach from "skip_local_output". But it Works Today, so there's that...

Extended the functionality that mreid added for counters to local jobs run with FileDriver.py. There's probably a better way to do this too, but this also works fine.