Remove .pyc files we leave around because of import.

def cleanup_pycache():
    """Remove .pyc files we leave around because of import.
    """
    try:
        for file in glob.glob('setup.py[co]'):
            os.remove(file)
        if isdir('__pycache__'):
            for file in glob.glob(join('__pycache__', 'setup.*.py[co]')):
                os.remove(file)
            if not glob.glob(join('__pycache__', '*')):
                os.rmdir('__pycache__')
    except (IOError, OSError):
        pass