pre-upload_unittest: convert mox to mock

We don't want to use mox anymore.

BUG=chromium:430770
TEST=unittests still pass

Change-Id: I5b09f6fcd5760c663c86d7787b8a48ea58605d90
Reviewed-on: https://chromium-review.googlesource.com/233780
Reviewed-by: Yu-Ju Hong <yjhong@chromium.org>
Tested-by: Mike Frysinger <vapier@chromium.org>
1 file changed