relax SVN archive

A quick release to fix the fatal 'devnull' ImportError (bug #6403). This bug effects those using
Python versions < 2.4 and prevents relax from starting up. The solution was to import the object
using a try statement to allow execution of the program. However if relax ever attempts to use
'devnull' a RelaxError is thrown, a message saying to upgrade to Python >= 2.4 is printed, and the
program terminates. This is currently only a problem in the test-suite.

The full list of changes is:

Features:
N/A

Changes:
N/A

Bugfixes:
* Added the missing PDB file used by one of the OpenDX tests of the relax test-suite. (bug
#6404)
* Fixed the fatal devnull import failure for Python versions < 2.4. (bug #6403)