check dlg connected before deleting

lib/session/call-session.js

@@ -546,7 +546,7 @@ class CallSession extends Emitter {
       const duration = moment().diff(this.dlg.connectTime, 'seconds');
       this.emit('callStatusChange', {callStatus: CallStatus.Completed, duration});
       this.logger.debug('CallSession: call terminated by jambones');
-      origDestroy();
+      if (dlg.connected) origDestroy();
     };
   }