Log Message:
Update to dovecot-1.0rc28.  From the release announcement mail:

Still a bit more fixes. My coding TODO list is again empty. Unless
something special happens in the next few weeks, I'll still make rc29
with the documentation included and v1.0 will be released April 13.

	* deliver + userdb static: Verify the user's existence from passdb,
	  unless allow_all_users=yes
	* dovecot --exec-mail: Log to configured log files instead of stderr
	* Added "-example" part to doc/dovecot-sql-example.conf and
	  doc/dovecot-ldap-example.conf. They are now also installed to
	  $sysconfdir with "make install".

	+ When copying/syncing a lot of mails, send "* OK Hang in there"
	  replies to client every 15 seconds so it doesn't just timeout the
	  connection.
	+ Added idxview and logview utilities to examine Dovecot's index files
	+ passdb passwd and shadow support blocking=yes setting now also
	+ mbox: If mbox file changes unexpectedly while we're writing to it,
	  log an error.
	+ deliver: Ignore -m "" parameter to make calling it easier.
	+ deliver: Added new -n parameter to disable autocreating mailboxes.
	  It affects both -m parameter and Sieve plugin's fileinto action
	- mbox: Using ~/ in the mail root directory caused a ~ directory to be
	  created (instead of expanding it to home directory)
	- auth cache: If unknown user was found from cache, we didn't properly
	  return "unknown user" status, which could have caused problems in
	  deliver.
	- mbox: Fixed "UID inserted in the middle of mailbox" in some
	  conditions with broken X-UID headers
	- Index view syncing fixes
	- rc27 didn't compile with some non-GCC compilers
	- vpopmail support didn't compile in rc27
	- NFS check with chrooting broke home direcotry for the first login
	- deliver: If user lookup returned "unknown user", it logged
	  "BUG: Unexpected input"
	- convert plugin didn't convert INBOX