Correct the value needed to disable auto-updates

Also remove Windows-style line endings.
Patch-contributed-by: Nasser Grainawi <nasser@codeaurora.org>

Review URL: http://codereview.chromium.org/541034

git-svn-id: svn://svn.chromium.org/chrome/trunk/tools/depot_tools@36145 0039d316-1c4b-4281-b951-d872f2087c98

README

@@ -36,11 +36,11 @@ This package contains:
 
   revert
     A small tool to quickly revert a change.
-
+
 Note: svn and python will be installed automatically if not accessible (on
-Windows only).
+Windows only).
 
 To update this distribution manually, run bootstrap\update.bat on Windows,
 or bootstrap/update.sh on Linux or Mac.
-
-To disable automatic updating, set the environment variable DEPOT_TOOLS_UPDATE=1
+
+To disable automatic updating, set the environment variable DEPOT_TOOLS_UPDATE=0