Reason: it breaks re-upload.

R=andybons@chromium.org,machenbach@chromiu.org,mmentovai@chromium.org
BUG=

Review URL: https://codereview.chromium.org/1810683003

git-svn-id: svn://svn.chromium.org/chrome/trunk/tools/depot_tools@299354 0039d316-1c4b-4281-b951-d872f2087c98