Uncaught exception,,,,`handleData()` in irc.js does not handle `conn` value correctly

[lgxZJ]

Error condition: connect a irc network using node-irc, when unplug the network cable, wait for some seconds, replug the cable. Error reason: unplug the cable caused the connectionTimedOut() function of CyclingPingTimer set conn to null, when replug the cable, (on my condition)an error message comed which caused self.conn.cyclingPingTimer.notifyOfActivity(); to be executed, at that time self.conn is null.