Impacted versions:
11.0
Steps to reproduce:
Translations -> Synchronize Terms -> Language : Arabic
Current behavior:
Error:
Odoo Server Error
```
Error:
Traceback (most recent call last):
  File "/Users/rubyonrails/odoo/odoo/http.py", line 648, in _handle_exception
    return super(JsonRequest, self)._handle_exception(exception)
  File "/Users/rubyonrails/odoo/odoo/http.py", line 309, in _handle_exception
    raise pycompat.reraise(type(exception), exception, sys.exc_info()[2])
  File "/Users/rubyonrails/odoo/odoo/tools/pycompat.py", line 86, in reraise
    raise value
  File "/Users/rubyonrails/odoo/odoo/http.py", line 685, in dispatch
    result = self._call_function(**self.params)
  File "/Users/rubyonrails/odoo/odoo/http.py", line 341, in _call_function
    return checked_call(self.db, *args, **kwargs)
  File "/Users/rubyonrails/odoo/odoo/service/model.py", line 97, in wrapper
    return f(dbname, *args, **kwargs)
  File "/Users/rubyonrails/odoo/odoo/http.py", line 334, in checked_call
    result = self.endpoint(*a, **kw)
  File "/Users/rubyonrails/odoo/odoo/http.py", line 929, in __call__
    return self.method(*args, **kw)
  File "/Users/rubyonrails/odoo/odoo/http.py", line 514, in response_wrap
    response = f(*args, **kw)
  File "/Users/rubyonrails/odoo/addons/web/controllers/main.py", line 920, in call_button
    action = self._call_kw(model, method, args, {})
  File "/Users/rubyonrails/odoo/addons/web/controllers/main.py", line 908, in _call_kw
    return call_kw(request.env[model], method, args, kwargs)
  File "/Users/rubyonrails/odoo/odoo/api.py", line 689, in call_kw
    return call_kw_multi(method, model, args, kwargs)
  File "/Users/rubyonrails/odoo/odoo/api.py", line 680, in call_kw_multi
    result = method(recs, *args, **kwargs)
  File "/Users/rubyonrails/odoo/odoo/addons/base/module/wizard/base_update_translations.py", line 42, in act_update
    tools.trans_load_data(self._cr, buf, 'csv', this.lang, lang_name=lang_name)
  File "/Users/rubyonrails/odoo/odoo/tools/translate.py", line 1034, in trans_load_data
    fileobj.seek(0)
ValueError: I/O operation on closed file.
```
Expected behavior:
Do Synchronize Terms


_name = 'base.update.translations'
    @api.model
    def _get_languages(self):
        langs = self.env['res.lang'].search([('active', '=', True), ('translatable', '=', True)])
        return [(lang.code, lang.name) for lang in langs]
    @api.model
    def _default_language(self):
        if self._context.get('active_model') == 'res.lang':
            lang = self.env['res.lang'].browse(self._context.get('active_id'))
            return lang.code
        return False
    lang = fields.Selection(_get_languages, 'Language', required=True,
                            default=_default_language)
    @api.model
    def _get_lang_name(self, lang_code):
        lang = self.env['res.lang'].search([('code', '=', lang_code)], limit=1)
        if not lang:
            raise UserError(_('No language with code "%s" exists') % lang_code)
        return lang.name
    @api.multi
    def act_update(self):
        this = self[0]
        lang_name = self._get_lang_name(this.lang)
        with contextlib.closing(io.BytesIO()) as buf:
            tools.trans_export(this.lang, ['all'], buf, 'csv', self._cr)
            tools.trans_load_data(self._cr, buf, 'csv', this.lang, lang_name=lang_name)
        return {'type': 'ir.actions.act_window_close'}