[XML-SIG] Regression tests fails in Python 2.1

[Martin v. Loewis]

> I've changed regrtest.py (see below) so that you can add versioned test 
> files to the output dir, in this case "test_pyexpat.2.1". Shall I commit 
> those changes?

No. I'd rather prefer if the test case worked the same way for all
Python versions. Please have a look at revision 1.7 of
test_pyexpat.py; I already had the code to do this. Unfortunately,
Fred has overwritten these changes later.

Regards,
Martin