[imp] mail_digest: fallback to default website

Depending on the request  might fail
nevertheless the website should be there to be found.
Fallback to search and use it if possible for digest' site name

mail_digest/models/mail_digest.py

@@ -131,12 +131,19 @@ class MailDigest(models.Model):
         # default to company
         name = self.env.user.company_id.name
         if 'website' in self.env:
+            # TODO: shall we make this configurable at digest or global level?
+            # Maybe you have a website but
+            # your digest msgs are not related to it at all or partially.
+            ws = None
             try:
                 ws = self.env['website'].get_current_website()
                 name = ws.name
             except RuntimeError:
-                # RuntimeError: object unbound -> no website request
-                pass
+                # RuntimeError: object unbound -> no website request.
+                # Fallback to default website if any.
+                ws = self.env['website'].search([], limit=1)
+            if ws:
+                name = ws.name
         return name
 
     @api.multi