plugin OTR: ignore messages from sender without resource or from own jid

sat/plugins/plugin_sec_otr.py

@@ -733,6 +733,10 @@ class OTR(object):
         if message_elt.getAttribute("type") == C.MESS_TYPE_GROUPCHAT:
             # OTR is not possible in group chats
             return True
+        from_jid = jid.JID(message_elt['from'])
+        if not from_jid.resource or from_jid.userhostJID() == client.jid.userhostJID():
+            # OTR is only usable when resources are present
+            return True
         if client.profile in self.skipped_profiles:
             post_treat.addCallback(self._receivedTreatmentForSkippedProfiles)
         else: