This fix is needed for our own build slaves to work properly on Windows and is caused by the hacky way we created the Libvpx waterfall to avoid duplicating unnecessary Python code.
TBR=phoglund
BUG=None
TEST=Tested on Windows build slave.
Review URL: https://webrtc-codereview.appspot.com/639009
git-svn-id: http://webrtc.googlecode.com/svn/trunk@2387 4adac7df-926f-26a2-2b94-8c16560cd09d
