Tested by running gclient sync a couple of times from a Cygwin shell.

R=dpranke@chromium.org
CC=scottmg@chromium.org,thakis@chromium.org,maruel@chromium.org
BUG=335180

Review URL: https://codereview.chromium.org/140843004

git-svn-id: svn://svn.chromium.org/chrome/trunk/tools/depot_tools@245315 0039d316-1c4b-4281-b951-d872f2087c98