Enable implicit auto-upgrade to python 2.7.5.

This will automatically upgrade python to 2.7.5 unless
set DEPOT_TOOLS_PYTHON_275=0
is used.

R=iannucci@chromium.org
BUG=241769

Review URL: https://codereview.chromium.org/53313002

git-svn-id: svn://svn.chromium.org/chrome/trunk/tools/depot_tools@235140 0039d316-1c4b-4281-b951-d872f2087c98

bootstrap/win/win_tools.bat

@@ -113,8 +113,8 @@ goto :END
 
 
 :PYTHON_CHECK
-if "%DEPOT_TOOLS_PYTHON_275%" == "1" goto :PY275_CHECK
-goto :PY26_CHECK
+if "%DEPOT_TOOLS_PYTHON_275%" == "0" goto :PY26_CHECK
+goto :PY275_CHECK
 
 
 :PY26_CHECK