Retries are no longer necessary, since the Git wrapper will retry all
transient Git operations.

BUG=None
TEST=None
R=hinoka@chromium.org, iannucci@chromium.org

Change-Id: I18f066004992c98e54665833360944cc7d6550cc
Reviewed-on: https://chromium-review.googlesource.com/506375
Commit-Queue: Daniel Jacques <dnj@chromium.org>
Reviewed-by: Robbie Iannucci <iannucci@chromium.org>
Reviewed-by: Ryan Tseng <hinoka@chromium.org>