opening local nnimap server through shell stream fails at startup

[Pedro Silva <psilva@pedrosilva.pt>]

When I first start gnus, the connection to a local IMAP server (dovecot)
via 'shell fails. It appears that 'nnimap-stream' is set to its default
'undecided', which means it first tries to use 'ssl, leading to the
following error:

--8<---------------cut here---------------start------------->8---
Unable to open server nnimap+dovecot due to: dovecot/993 System error
--8<---------------cut here---------------end--------------->8---

Of course, this doesn't happen when dovecot is listening on
localhost:993/ssl (but it *does* happen on localhost:143/network), but
I'd rather use the tunnel method.

Here is the relevant configuration:

--8<---------------cut here---------------start------------->8---
(add-to-list
 'gnus-secondary-select-methods '(nnimap "dovecot"
                                         (nnimap-address "localhost")
                                         (nnimap-stream shell)
                                         (nntp-authinfo-file "~/.authinfo.gpg")
                                         (nnimap-shell-program
					  "/usr/lib/dovecot/imap")
                                         (nnir-search-engine imap)))
--8<---------------cut here---------------end--------------->8---

I then go to the server buffer and close the connection, after which
opening it again works fine, although I tipically get one or more
duplicate {nnimap:dovecot} entries.

This might conceivably have something to do with the thread started
yesterday:

http://thread.gmane.org/op.wwpniicrgfp24t@nolsbang01.one.steria.dom

Any ideas on what's going on? Thanks for the help.
-- 
Pedro