Bug#253978: kmail: IMAP mailbox unread count is wrong

[Vassilii Khachaturov <vassilii@tarunz.org>]

Additional info on the bug.
1) when I get new mail in the !bulk folder (e.g. from the bugs.d.o 
confirmation about this bug), while viewing INBOX, i see the !bulk counter 
increase from 15 to 16
2) when I then select !bulk the counter goes to 1 (correct), and I see 4 msgs 
there, 3 old and the 1 new. The counter gets correctly updated both on the 
folders pane and in the system tray
3) when I view the new msg in !bulk, the counter goes down to 0
4) I then again select INBOX, or I can stay with !bulk selected
5) on the next periodical check of my IMAP account, it goes back up to 15
(when I select the !bulk folder again, there is nothing new there). At this
moment the counter stays wrong until new mail arrives in the folder.

Vassilii