lower some of the logging calls in core/log.py to DEBUG
lower some of the logging calls in core/log.py to DEBUG

The log emissions in this change should be DEBUG rather than
INFO.  Either a jobtype would be logging the file path, the
information we're logging is not useful outside of debug/testing or
there are other way we'd find out there's a problem (such as an
exception being raised).

pyfarm/pyfarm-agent,guidow/pyfarm-agent,pyfarm/pyfarm-agent,pyfarm/pyfarm-agent,guidow/pyfarm-agent,guidow/pyfarm-agent