[sync] Duplicates and slow sync

[Karsten Fourmont]

Chuck Hagenbuch wrote:
> Quoting Jan Schneider <jan at horde.org>:
> 
>> While trying to track down why slow sync or refresh from server didn't
>> work, I found some code in Backend.php that checks whether we have
>> already seen events from the server on the client. The comments is:
>>
>> // For slow sync (ts = 0), do not add data for which
>> // we have a locid again. This is a heuristic to
>> // avoid duplication of entries.
>>
>> I understand the rationale behind it, we try to avoid duplicate events
>> on the client. But doesn't this prohibit the purpose of slow syncs?
>> It's supposed to *force* reloading of the device/client. 

Right. I removed this. Now a slow sync (as well as refresh from server) 
really returns all data.

Karsten