Blender Git Loki

Switch linux buildbot to custom built python2.7

New scons discontinued support of python2.6, so we needed
to build just another python in the release and buildbot
environment.

Hope latest scons upgrade a least bring new msvs support
and not only lead to just-another-frustration.

There might be some more upcoming commits, because you
never can be sure there's no typos in the buidbot script
for until you actually fire the builder up.