Fix windows startup script's addition to path
Fix windows startup script's addition to path

BUG=skia:

Review-Url: https://codereview.chromium.org/2044543003

google/skia-buildbot,google/skia-buildbot,google/skia-buildbot,google/skia-buildbot,google/skia-buildbot,google/skia-buildbot,google/skia-buildbot,google/skia-buildbot