Webkitpy's version check should not throw any exception.
Webkitpy's version check should not throw any exception.

The python version checker inside the webkitpy uses Python 2 syntax
to display the error message on the stderr. With Python 3 that code
throws an error. Using directly the stderr as a file object will
prevent the error.

BUG=408166
TEST=webkit-patch -h

Review URL: https://codereview.chromium.org/505353004

git-svn-id: bf5cd6ccde378db821296732a091cfbcf5285fbd@180994 bbb929c8-8fbe-4397-9dbb-9b2b20218538

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