on some installations, the DRE won't startup due to an existing Python installation

[GoogleCodeExporter]

Reported by Simon Su:

C:\Program Files\DeVIDE-RE>dre python -v

'import site' failed; use -v for traceback
Traceback (most recent call last):
  File "C:\Program Files\DeVIDE-RE\\dre.py", line 7, in <module>
    import ConfigParser

With Simon's help diagnosing, it seems like the DRE python might be 
breaking due to attempting to import modules from the system and/or user-
site directory.  We could suppress both of these by adding -S (suppress 
system site) and -s (suppress user site) to the python invocation in the 
dre driver shell scripts.

Will wait to confirm that this fixes the problem and doesn't break anything 
else before committing to SVN.

Original issue reported on code.google.com by cpbotha on 22 Oct 2009 at 7:45