[horde] Horde_ActiveSync 2.28.0 break INBOX sync

[Samuel Wolf]

Hi,

upgrade today to Horde_ActiveSync 2.28.0 and Horde_Core 2.20.1.
After this upgrade *all* my clients (Android 4.4.2 / 5.0.2 and  
TouchDown APP) stop with the INBOX sync, remove all states does not  
help.

Device is able to send messages, I don't test the sync of other  
folders then INBOX.
For the moment I downgrade to 2.27.1 and 2.20.0 and sync work again.

Samuel