python: Continuing message re-use fix

[David Bremner]

Floris Bruynooghe <flub at devork.be> writes:

> Hi,
>
> This builds on the patch by Anton Khirnov to fix the message re-use
> that is possible when accessing messages from a thread.  I started
> with just addressing my own comments on this patch, but evolved it
> into switching the logic around and leave the normal Message object
> untouched.  Instead I created a new OwnedMessage which is used by
> the Thread which does not free itself on __del__().  I think this
> is preferable because the other iterators, mainly Database.messages(),
> do not allow retrieving messages more than once since the query object
> is hidden from the API.
>
> I've left the original commit in this patch series to not alter any
> contributions.
>
> Cheers,
> Floris

Revised series merged to master and release.

Thanks for your help with these updates.

d