misleading error message when "freezer" doesn't exist

[Ambrose Li <news-misc@mingpaoxpress.com>]

This is 2.99.49p8-try1. Looking at the diffs between try1 and final,
final should also exhibit this behaviour.

If the freezer directory doesn't exist but a message is tagged for
freezing, the smtpserver reports that

308w    452 4.3.0 Requested action not taken: insufficient storage
308#    aborted (1335 bytes): message file close failed

This got me nervous about a week :-(

This occurs because _mail_close_() doesn't differentiate between
the different kinds of close failures so the smtpserver only knows
that the "message file close failed" without knowing why. I originally
thought that the "insufficient storage" is a new spam error until I
saw a real spam error message in the log file.

--
Ambrose C. Li <acli@mingpaoxpress.com>
,,Programmer-analyst'' / system administrator / PC user support
    Ming Pao Newspapers (Canada) Ltd. EDP department
      1355 Huntingwood Dr., Scarborough (Ont.), Canada  M1S 3J1  +1(416)321-0088