Update enumerate_files.py to ignore "hidden" files. Skip over files that begin with '.' since they are often hidden temporary files. BUG=angle:553 Change-Id: I74f8412e6959c49bfca7f0ae063af42027e12549 Reviewed-on: https://chromium-review.googlesource.com/188035 Reviewed-by: Jamie Madill <jmadill@chromium.org> Reviewed-by: Shannon Woods <shannonwoods@chromium.org> Tested-by: Geoff Lang <geofflang@chromium.org>