[bug-mailutils] imap4d protocol bug

[Simon Josefsson]

Compare:

,----
| 40 SELECT "INBOX"
| * OK [UIDVALIDITY 0] UID valididy status
| * OK [UIDNEXT 0] Predicted next uid
| * FLAGS (\Answered \Flagged \Deleted \Seen \Draft)
| * OK [PERMANENTFLAGS (\Answered \Deleted \Seen)] Permanent flags
| 40 OK [READ-WRITE] SELECT Completed
`----

with

,----
| 6.3.1.  SELECT Command
| 
|    Arguments:  mailbox name
| 
|    Responses:  REQUIRED untagged responses: FLAGS, EXISTS, RECENT
|                OPTIONAL OK untagged responses: UNSEEN, PERMANENTFLAGS
`----

I believe you have to return the EXISTS untagged response too.