Change rebaselining tool to pull win baselines from xp bot

instead of vista bot which is not stable now.

TBR=dpranke
TEST=none
BUG=none

Review URL: http://codereview.chromium.org/224013

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@27132 0039d316-1c4b-4281-b951-d872f2087c98