This was broken by 209a681f,
which replaced self.run() with git_common.run(), thus
bypassing self.run()'s dry_run check.

Bug: 788562
Change-Id: I9964c169b0ff56778c4660acab7ef7c010e37a36
Reviewed-on: https://chromium-review.googlesource.com/797611
Commit-Queue: Aaron Gable <agable@chromium.org>
Reviewed-by: Andrii Shyshkalov <tandrii@chromium.org>