[horde] Bug on renaming subfolders with Outlook 2013

[Patrick De Zordo]

Hi there,
found new bug:

Whenever I create a subfolder to INBOX with Outlook (let's call it 
"folder") it's created as expected.
But when I'm going to rename it later (let's call it "folder_renamed") 
it disappears from Outlook; in IMAP filesystem the folder is renamed.
So the command RENAME was sent by Horde to IMAP, this is correct; but 
probably there is not coming back the right answer to OL from ActiveSync.

Since Outlook will not reread the IMAP "subscriptions" file very often 
(I suppose never ever, just on profile creation) the renamed folder will 
never reappear.

Solution is to create a folder with the changed name "folder_renamed"; 
folder reappears.