[FIX] im_livechat: use correct url to find rules that apply

The problem was that, when calling 'match_rules()' from the loader template,
we compared the wrong url with the url regexp defined in rules. Indeed, we used
the url of the page we were leaving, not the one we were going to.

We thus need to know if we are coming from the controller, or from the loader
template directly as the way to get the correct url differs.

Courtesy of JEM

addons/im_livechat/controllers/main.py

@@ -29,7 +29,7 @@ class LivechatController(http.Controller):
     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'].match_rules(request, channel.id, username=username)
+        info = request.env['im_livechat.channel'].with_context(from_external_page=True).match_rules(request, channel.id, username=username)
         return request.render('im_livechat.loader', {'info': info, 'web_session_required': True}) if info else False
 
     @http.route('/im_livechat/available', type='json', auth="public")

addons/im_livechat/models/im_livechat_channel.py

@@ -207,7 +207,10 @@ class ImLivechatChannel(models.Model):
             if country_ids:
                 country_id = country_ids[0].id
         # extract url
-        url = request.httprequest.headers.get('Referer') or request.httprequest.base_url
+        if self.env.context.get('from_external_page', False):
+            url = request.httprequest.headers.get('Referer')
+        else:
+            url = request.httprequest.base_url
         # find the match rule for the given country and url
         rule = self.env['im_livechat.channel.rule'].sudo().match_rule(channel_id, url, country_id)
         if rule: