[horde] Portal blocks and some other prefs not migrated

[stephan at admin.nabira.de]

> Please try again with the Horde releases from today. They fix a bug  
> where Horde login tasks were not always executed.

After some more tests the portal block migration seems to work  
alright. Alternate email identities are not migrated, but I am not  
sure this was supported anyway. It is not much annoying to me, so I  
won't request for any fixes.

Thanks for your support.

Stephan