Fix exception logging.

Exception objects do not have msg attributes they have message
attributes. Use message instead of msg. Also use logger.warning()
instead of logger.warn() to be consistent with python documentation.

Change-Id: I49be960202f3fa1add19f3068ff824ae9d7f8314

elastic_recheck/bot.py

@@ -198,8 +198,8 @@ class RecheckWatch(threading.Thread):
                         event,
                         debug=not self.commenting)
             except er.ResultTimedOut as e:
-                self.log.warn(e.msg)
-                self._read(msg=e.msg)
+                self.log.warning(e.message)
+                self._read(msg=e.message)
             except Exception:
                 self.log.exception("Uncaught exception processing event.")