Added a property method to return what the 'session' field used to return,

but based on the 'sessions' m2m field filtered with the meeting agenda.
This is right for the main meeting agenda, but not for personal schedule
layouts, so this isn't a final fix.
 - Legacy-Id: 6436

ietf/meeting/models.py

@@ -248,6 +248,11 @@ class TimeSlot(models.Model):
     #
 
     @property
+    def session(self):
+        sessions = self.sessions.filter(scheduledsession__schedule=self.meeting.agenda)
+        session = sessions.get() if sessions.count() == 1 else None
+        return session
+
     def time_desc(self):
         return u"%s-%s" % (self.time.strftime("%H%M"), (self.time + self.duration).strftime("%H%M"))