Remove 'out' variable reference.  If subprocess.communicate()
throws an exception, out cannot contain data.

BUG=236073
TBR=cmp

Review URL: https://chromiumcodereview.appspot.com/14386022

git-svn-id: svn://svn.chromium.org/chrome/trunk/tools/depot_tools@196904 0039d316-1c4b-4281-b951-d872f2087c98