[Dovecot] bug report, from apple.com

[Jason Fesler]

> But the problem is that it asks for separator for the "" namespace,
> which doesn't exist. Dovecot does return the separator as long as it can
> find a namespace for it.

The RFC specifies that as a possibility.  From what I'm reading,
'LIST "" ""'  should return the root and the seperator both.
(rfc2060, 6.3..8.)

Maybe we should instead put the burden on the operator to define the 
answer to both questions, instead of guessing.

(hours later)..  Actually, what may instead be prefered, is to advise
in the sample conf they need at least one name space with an empty prefix 
setting; and if their default name space has a non-empty prefix, 
to create an empty prefix hidden name space that has the same 
mailbox location.