Fix a bug that a buffer is not created for a personal message.
Fix a bug that a buffer is not created for a personal message.

It should be created manually.

hachibasu/koko,KokoIRC/koko,KokoIRC/koko,noraesae/koko,woss/koko,alienxp03/koko,noraesae/koko,alienxp03/koko,woss/koko,hachibasu/koko,alienxp03/koko,hachibasu/koko,KokoIRC/koko,noraesae/koko,woss/koko