Return a list of known distutils servers for collective.dist.

        If the config has an old pypi config, remove the default pypi
        server from the list.

def distutils_servers(self):
        """Return a list of known distutils servers for collective.dist.

        If the config has an old pypi config, remove the default pypi
        server from the list.
        """
        if not multiple_pypi_support():
            return []
        try:
            raw_index_servers = self.config.get('distutils', 'index-servers')
        except (NoSectionError, NoOptionError):
            return []
        ignore_servers = ['']
        if self.is_old_pypi_config():
            # We have already asked about uploading to pypi using the normal
            # upload.
            ignore_servers.append('pypi')
            # Yes, you can even have an old pypi config with a
            # [distutils] server list.
        index_servers = [
            server.strip() for server in raw_index_servers.split('\n')
            if server.strip() not in ignore_servers]
        return index_servers