Determine if the working directory has been changed.

def dirty(name,
          target,
          user=None,
          username=None,
          password=None,
          ignore_unversioned=False):
    '''
    Determine if the working directory has been changed.
    '''
    ret = {'name': name, 'result': True, 'comment': '', 'changes': {}}
    return _fail(ret, 'This function is not implemented yet.')