Pull a file down from the file server and store it in the minion
        file cache

def cache_file(self, path, saltenv='base', cachedir=None, source_hash=None):
        '''
        Pull a file down from the file server and store it in the minion
        file cache
        '''
        return self.get_url(
            path, '', True, saltenv, cachedir=cachedir, source_hash=source_hash)