[Kst] Strange problem using the change data file tool

[Brisset, Nicolas]

> > Why is that so ? If a datasource provides efficient 
> understands...() 
> > and
> > fieldListFor...() methods, I believe auto-detection can 
> live without 
> > needing to call the constructor. And if it does call it, then for 
> > those sources that seem to be able to read the file, the instance 
> > should be kept.
> 
>   Can you find where these instantiations are coming from?
It seems that showPage() creates a first instance, and finished() needs
another one for some reason I have not yet understood. Interestingly,
the KST::dataSourceList.lock().writeLock() method is only called in one
place. I expected a symmetrical construct for removing a datasource, but
I did not find it. To sum up, I haven't yet found who destroys the first
instance, but for sure it disappears between showPage() and finished().

Nicolas