fromupstream: fix pylint error: Redefining built-in 'file'

Apparently the commit bdbb9cc2c9dc ("fromupstream: Tag commits with
BACKPORT if appropriate") was submitted without running (or with
ignoring) the pre-upload hooks.  Thus it wasn't pyling clean.  After
that patch, we get this warning:

  W: 29, 8: Redefining built-in 'file' (redefined-builtin)

Let's fix it.

BUG=None
TEST=No more pylint errors

Change-Id: Iee6ececc7ac459b91d6a9328c80ad0d1e9195bcf
Reviewed-on: https://chromium-review.googlesource.com/1035455
Commit-Ready: Douglas Anderson <dianders@chromium.org>
Tested-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Guenter Roeck <groeck@chromium.org>
1 file changed