plugin XEP-0313: log issues in addToHistory instead of raising error

sat/plugins/plugin_xep_0313.py

@@ -135,7 +135,15 @@ class XEP_0313(object):
                         continue
                     # adding message to history
                     mess_data = client.messageProt.parseMessage(fwd_message_elt)
-                    yield client.messageProt.addToHistory(mess_data)
+                    try:
+                        yield client.messageProt.addToHistory(mess_data)
+                    except exceptions.CancelError as e:
+                        log.warning(
+                            u"message has not been added to history: {e}".format(e=e))
+                    except Exception as e:
+                        log.error(
+                            u"can't add message to history: {e}\n{xml}"
+                            .format(e=e, xml=mess_elt.toXml()))
 
         if not count:
             log.info(_(u"We have received no message while offline"))