Log Message:
Update to dovecot-1.0rc16.  From the release announcement mail:

If you've had problems with getting errors about index files
sometimes being corrupted, please try if this release fixes it. If
you've reported any bugs that this release hasn't fixed, please
report them again so I know they still didn't get fixed and that I
didn't forget them.

	* IMAP: When trying to fetch an already expunged message, Dovecot used
	  to just disconnect client. Now it instead replies with dummy NIL
	  data.
	* Priority numbers in plugin names have changed. If you're installing
	  from source, you should delete the existing plugin files before
	  installing the new ones, otherwise you'll get errors.
	* Maildir: We're using rename() to move files from tmp/ to new/ now.
	  See http://wiki.dovecot.org/MailboxFormat/Maildir -> "Issues with
	  the specification" for reasoning why this is safe. This makes saving
	  mails faster, and also makes Dovecot usable with Mac OS X's HFS+
	  (after you also set dotlock_use_excl=yes, see below).

	+ Added dotlock_use_excl setting. If enabled, dotlocks are created
	  directly using O_EXCL flag, instead of by creating a temporary file
	  which is hardlinked. O_EXCL is faster, but may not work with NFS.
	+ If Dovecot crashes with Linux or Solaris, it'll log a
	  "Raw backtrace". It's worse than gdb's backtrace, but better than
	  nothing.
	+ Added maildir_copy_preserve_filename=yes setting.
	+ Added a lazy-expunge plugin to allow users to unexpunge their mails.
	+ maildir quota: Added ignore setting to maildir quota, which allows
	  ignoring quota in Trash mailbox.
	+ dict quota: If dictionary doesn't yet contain the quota, calculate
	  it by going through all the mails in all the mailboxes.
	+ login_log_format_elements: Added %a=local port and %b=remote port
	+ Added -i and -o options to rawlog to restrict logging only to
	  input or output.
	- Doing a STATUS command for a selected mailbox (not a recommended
	  IMAP client behavior) caused Dovecot to sync the mailbox silently.
	  This could have lost eg. EXPUNGE events from clients, causing them
	  to use wrong sequence numbers.
	- deliver was treating boolean settings set to "no" as if they were
	  "yes" (they were supposed to be commented out for "no")
	- Running "dovecot" with -a or -n option while Dovecot was running
	  deleted all authentication sockets, which caused all the future
	  logins to fail.
	- maildir: RENAME and DELETE didn't touch control directory if it was
	  different from maildir or index dir.
	- We treated internal userdb lookup errors as "user unknown" errors.
	  In such situations this caused deliver to think the user didn't
	  exist and the mail get bounced.
	- pam: Setting cache_key crashed
	- shared maildir: dovecot-keywords file's mode wasn't taken from
	  dovecot-shared file.
	- dovecotpw wasn't working with PowerPC