testrunner: respect verbosity setting when cleaning pycs

"manage test" currently throws a large number of info messages when the pyc's are purged.  This PR respects the verbosity setting, and by default, these info messages will not be seen. 

Also fixing up LOG.logging import to the preferred style.

To test: 
$./manage.py test
previously each pyc deleted would give an info message.

To see the info messages (+other testing messages) use:
$./manage.py test --verbosity=2