[Dovecot] when the user has no home directory

[Dave Yost]

A user on our server for some reason didn't have a home directory. As 
a result, the pop3 server was complaining. Apple's Mail app reported 
that the server said:

   The attempt to send data to the server "(null)" failed.

It would be nice if the server would say something to the effect that 
the connection failed because the user account has no home directory.

Thanks