BUG=
TESTS=
alpaca(gsutil_version) ~/depot_tools$ ./gsutil.py version                                                                                                                                                   
gsutil version: 4.13

Review URL: https://codereview.chromium.org/1237013003

git-svn-id: svn://svn.chromium.org/chrome/trunk/tools/depot_tools@296023 0039d316-1c4b-4281-b951-d872f2087c98