Fix test_tasks.test_optional_args_in_tasks under PyPy
Fix test_tasks.test_optional_args_in_tasks under PyPy

PyPy apparently creates distinct string objects here.

cecedille1/paver,gregorynicholas/paver,thedrow/paver,phargogh/paver,nikolas/paver,gregorynicholas/paver,cecedille1/paver