[ChromeOS] Fix a problem that fails to get oauth token for official build.
[ChromeOS] Fix a problem that fails to get oauth token for official build.

Product name is encoded twice and thus causing oauth token fetch request to fail on official Chrome build: "Google Chrome" becomes "Google%2520Chrome" in request URL and causes server to return 400.

BUG=chromium-os:19352
TEST=Verify fix for chromium-os:19352.


Review URL: http://codereview.chromium.org/7669062

git-svn-id: de016e52bd170d2d4f2344f9bf92d50478b649e0@97583 0039d316-1c4b-4281-b951-d872f2087c98

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