[FIX] website_blog: handle replies to Blog Post Published as notes

As the Blog Post Published message is posted on a channel every reply
to this message is also posted on the blog. However blogs may holds
lot of followers not necessarily interested in being spammed by answers
to that message. We consider now that those replies are notes to avoid
spam. Blog managers can follow the note subtype to be warned about
those messages.

addons/website_blog/models/website_blog.py

@@ -4,7 +4,7 @@ from datetime import datetime
 import lxml
 import random
 
-from openerp import tools
+from openerp import api, tools
 from openerp import SUPERUSER_ID
 from openerp.addons.website.models.website import slug
 from openerp.osv import osv, fields
@@ -37,6 +37,20 @@ class Blog(osv.Model):
             BlogPost.write(cr, uid, post_ids, {'active': vals['active']}, context=context)
         return res
 
+    @api.multi
+    def message_post(self, parent_id=False, subtype=None, **kwargs):
+        """ Temporary workaround to avoid spam. If someone replies on a channel
+        through the 'Presentation Published' email, it should be considered as a
+        note as we don't want all channel followers to be notified of this answer. """
+        self.ensure_one()
+        if parent_id:
+            parent_message = self.env['mail.message'].sudo().browse(parent_id)
+            if parent_message.subtype_id and parent_message.subtype_id == self.env.ref('website_blog.mt_blog_blog_published'):
+                if kwargs.get('subtype_id'):
+                    kwargs['subtype_id'] = False
+                subtype = 'mail.mt_note'
+        return super(Blog, self).message_post(parent_id=parent_id, subtype=subtype, **kwargs)
+
     def all_tags(self, cr, uid, ids, min_limit=1, context=None):
         req = """
             SELECT