This is slightly messy but seemingly necessary because cygwin doesn't consider a .bat file when running the command without the .bat extension.

TEST=shouldn't break everything
BUG=none
Review URL: http://codereview.chromium.org/125032

git-svn-id: svn://svn.chromium.org/chrome/trunk/tools/depot_tools@18337 0039d316-1c4b-4281-b951-d872f2087c98