It seems like line is always a string, not bytes; this change
seems to make it work with both Python 2 and 3 (at least,
"gclient sync" looks correct and doesn't throw exceptions)

Bug: 984182
Change-Id: Iaa09e08d4eda0ccb54afa5598bac6231319d6c3d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/1744766
Auto-Submit: Christian Biesinger <cbiesinger@chromium.org>
Commit-Queue: Edward Lesmes <ehmaldonado@chromium.org>
Reviewed-by: Edward Lesmes <ehmaldonado@chromium.org>