Tab-complete 'creds' commands.

def complete_hosts(self, text, line, begidx, endidx):
        "Tab-complete 'creds' commands."

        commands = ["add", "remove", "dc"]

        mline = line.partition(' ')[2]
        offs = len(mline) - len(text)
        return [s[offs:] for s in commands if s.startswith(mline)]