cros_generate_update_payload: Add some missing {}s, [[]]s, and ""s.

I'm about to make a bunch of changes to cros_generate_update_payload, and
rather than imitating the existing style mistakes or being inconsistent, I'm
fixing the problems up front.

BUG=None
TEST=Ran paygen_payload successfully.

Change-Id: If9c4a9da4de2ab458ca9b43976aa0a64d5738937
Reviewed-on: https://chromium-review.googlesource.com/223126
Reviewed-by: Mike Frysinger <vapier@chromium.org>
Commit-Queue: Gabe Black <gabeblack@chromium.org>
Tested-by: Gabe Black <gabeblack@chromium.org>
1 file changed