2.7.5 has bug http://bugs.python.org/issue17998 in re package that is affecting
the chromium team so it can't be used. The bug is fixed in 2.7.6.

This update still respects DEPOT_TOOLS_PYTHON_275=0. Since the name doesn't
represent what is being installed, it also respects
DEPOT_TOOLS_PYTHON_27=0.

R=iannucci@chromium.org
BUG=241769

Review URL: https://codereview.chromium.org/73013003

git-svn-id: svn://svn.chromium.org/chrome/trunk/tools/depot_tools@235384 0039d316-1c4b-4281-b951-d872f2087c98