new DateTime rounding impacts solr diff

Problem

In https://github.com/4teamwork/ftw.solr/pull/158 we fixed a rounding issue in the conversion of tope DateTime objects strings for indexing in solr. The problem is that because the rounding is now basically a floor instead of a round, 50% of the modified dates are not in sync with what they should be if the new rounding were applied to store them in solr, which means that diff thinks that 50% of the objects are out of sync.

Proposed solution

We update the modified index in solr to reflect the new rounding. We have to be careful though and only reindex modified for objects that actually are in sync, otherwise we would loose the information of which objects are really out of sync.

Implementation

upgrade step in ftw.solr to update the modified index
use brains as source for the modified date, not the actual objects

4teamwork / ftw.solr