paycheck: Allow minor version 3 in applier.

Also fixed nits in checker.

BUG=chromium:568473
TEST=./checker_unittest.py

Change-Id: Ia791f4dc636e9c3a2921aeaa5f9dd01c247bf5bb
Reviewed-on: https://chromium-review.googlesource.com/317780
Trybot-Ready: Sen Jiang <senj@chromium.org>
Tested-by: Sen Jiang <senj@chromium.org>
Reviewed-by: Alex Deymo <deymo@chromium.org>
Reviewed-by: Gilad Arnold <garnold@chromium.org>
Commit-Queue: Sen Jiang <senj@chromium.org>
3 files changed