Impacted versions:
10.0

Steps to reproduce:
From Chrome Versión 59.0.3071.115 (Build oficial) (64 bits)
with lang  spanish Latin America es_419
Go to http://247698-10-0-f3ee58.runbot8.odoo.com/?db=247698-10-0-f3ee58-all

Current behavior:

```python
2017-07-20 16:21:02,024 10584 INFO 247698-10-0-f3ee58-all odoo.sql_db: bad query: INSERT INTO "ir_translation" ("id", "lang", "src", "name", "type", "value", "state", "res_id") VALUES(nextval('ir_translation_id_seq'), 'es_419', 'Visitor, Administrator', 'mail.channel,name', 'model', 'Visitor, Administrator', 'translated', 81) RETURNING id
```
Expected behavior:
Chat being open

Video/Screenshot link (optional):
![image](https://user-images.githubusercontent.com/10233975/28430589-aa27e01a-6d46-11e7-82fc-18473bcf0e5e.png)


addons/im_livechat/controllers/main.py
@http.route('/im_livechat/external_lib.<any(css,js):ext>', type='http', auth='none')
    def livechat_lib(self, ext, **kwargs):
        
        xmlid = 'im_livechat.external_lib'
        files, remains = request.env["ir.qweb"]._get_asset_content(xmlid, options=request.context)
        asset = AssetsBundle(xmlid, files, remains)
        mock_attachment = getattr(asset, ext)()
        if isinstance(mock_attachment, list):  
            mock_attachment = mock_attachment[0]
        
        status, headers, content = binary_content(id=mock_attachment.id, unique=asset.checksum)
        content_base64 = base64.b64decode(content) if content else ''
        headers.append(('Content-Length', len(content_base64)))
        return request.make_response(content_base64, headers)
    @http.route('/im_livechat/support/<int:channel_id>', type='http', auth='public')
    def support_page(self, channel_id, **kwargs):
        channel = request.env['im_livechat.channel'].sudo().browse(channel_id)
        return request.render('im_livechat.support_page', {'channel': channel})
    @http.route('/im_livechat/loader/<int:channel_id>', type='http', auth='public')
    def loader(self, channel_id, **kwargs):
        username = kwargs.get("username", _("Visitor"))
        channel = request.env['im_livechat.channel'].sudo().browse(channel_id)
        info = request.env['im_livechat.channel'].get_livechat_info(channel.id, username=username)
        return request.render('im_livechat.loader', {'info': info, 'web_session_required': True}, headers=[('Content-Type', 'application/javascript')])
    @http.route('/im_livechat/init', type='json', auth="public")
    def livechat_init(self, channel_id):