This works around possible collisions with modules installed in the system 
python directories. 

See Gentoo Linux bug report: 
http://bugs.gentoo.org/349794

Patch by Mike Gilbert <floppymaster@gmail.com>

Review URL: http://codereview.chromium.org/6253009


git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@6463 ce2b1a6d-e550-0410-aec6-3dcde31c8c00