relax SVN archive

The variable 'as' was replaced by 'asec' since it is now a statement in Python >= 2.6.

This is similar to commit 46 in minfx:
https://mail.gna.org/public/minfx-commits/2009-05/msg00000.html

and as discussed in the thread starting at:
https://mail.gna.org/public/relax-devel/2010-02/msg00035.html
(Message-id: <4B737D34.4050008@...>)