Log Message:
Update to dovecot-1.0rc31.  From the release announcement mail:

mbox + NFS combination shouldn't break anymore. v1.0 still planned to
be released next friday.

	- mbox: Give "mbox file was modified while we were syncing" error only
	  if we detect some problems in the mbox file. The check can't be
	  trusted with NFS.
	- Convert plugin: If directory for destination storage doesn't exist,
	  create it.
	- Convert plugin: Mailbox names weren't converted in subscription list.